{"id":110690,"date":"2026-09-29T08:32:41","date_gmt":"2026-09-29T00:32:41","guid":{"rendered":"https:\/\/www.wsisp.com\/helps\/110690.html"},"modified":"2026-09-29T08:32:41","modified_gmt":"2026-09-29T00:32:41","slug":"python%e5%9f%ba%e7%a1%80%ef%bc%9a%e5%88%97%e8%a1%a8%e5%b8%b8%e7%94%a8%e6%96%b9%e6%b3%95%e4%b9%8b%e6%9f%a5%e6%89%be%e6%8e%92%e5%ba%8f%e4%b8%8e%e5%8f%8d%e8%bd%ac","status":"publish","type":"post","link":"https:\/\/www.wsisp.com\/helps\/110690.html","title":{"rendered":"Python\u57fa\u7840\uff1a\u5217\u8868\u5e38\u7528\u65b9\u6cd5\u4e4b\u67e5\u627e\u6392\u5e8f\u4e0e\u53cd\u8f6c"},"content":{"rendered":"

\u4e00\u3001\u5f00\u7bc7：\u627e\u5230\u5b83\u3001\u6392\u597d\u5b83\u3001\u7ffb\u8fc7\u6765<\/h3>\n

\u524d\u9762\u4e24\u7bc7\u6587\u7ae0\u6211\u4eec\u8be6\u7ec6\u62c6\u89e3\u4e86\u5217\u8868\u7684\u589e\u52a0\u548c\u5220\u9664\u65b9\u6cd5\u3002\u8fd9\u4e00\u7bc7\u662f\u5217\u8868\u65b9\u6cd5\u4e09\u90e8\u66f2\u7684\u7ec8\u7ae0，\u6211\u4eec\u8981\u641e\u5b9a\u4e09\u7c7b\u64cd\u4f5c：\u67e5\u627e（\u5728\u54ea\u91cc？\u6709\u51e0\u4e2a？）\u3001\u6392\u5e8f（\u4ece\u5c0f\u5230\u5927\u3001\u4ece\u5927\u5230\u5c0f\u3001\u6309\u81ea\u5b9a\u4e49\u89c4\u5219）\u3001\u53cd\u8f6c（\u5012\u8fc7\u6765）\u3002<\/p>\n

\u2328\ufe0f \u8fd9\u4e09\u7c7b\u64cd\u4f5c\u770b\u4f3c\u7b80\u5355，\u4f46\u5b9e\u9645\u5f00\u53d1\u4e2d\u7684\u5751\u53ef\u4e0d\u5c11\u3002index() \u627e\u4e0d\u5230\u5143\u7d20\u4f1a\u62a5\u9519\u600e\u4e48\u529e？sort() \u548c sorted() \u6709\u4ec0\u4e48\u533a\u522b？\u5982\u4f55\u7528 key \u53c2\u6570\u5b9e\u73b0\u81ea\u5b9a\u4e49\u6392\u5e8f？\u5217\u8868\u4e2d\u6709\u5b57\u5178\u600e\u4e48\u6309\u67d0\u4e2a\u5b57\u6bb5\u6392\u5e8f？reverse() \u548c reversed() \u548c [::-1] \u5230\u5e95\u8be5\u7528\u54ea\u4e2a？<\/p>\n

\u8fd9\u7bc7\u6587\u7ae0\u6211\u4f1a\u628a\u8fd9\u4e9b\u95ee\u9898\u4e00\u6b21\u6027\u8bb2\u6e05\u695a，\u8ba9\u4f60\u5728\u5199\u5217\u8868\u67e5\u627e\u6392\u5e8f\u4ee3\u7801\u65f6\u5fc3\u91cc\u6709\u5e95\u3001\u624b\u4e0a\u4e0d\u614c\u3002<\/p>\n

\u4e8c\u3001\u67e5\u627e\u2014\u2014index() \u548c count()<\/h3>\n

2.1 index()\u2014\u2014\u67e5\u627e\u5143\u7d20\u7684\u4f4d\u7f6e<\/h4>\n

fruits =<\/span> [<\/span>'\u82f9\u679c'<\/span>,<\/span> '\u9999\u8549'<\/span>,<\/span> '\u6a58\u5b50'<\/span>,<\/span> '\u8461\u8404'<\/span>,<\/span> '\u9999\u8549'<\/span>,<\/span> '\u897f\u74dc'<\/span>]<\/span><\/p>\n

# index(x)：\u67e5\u627ex\u7b2c\u4e00\u6b21\u51fa\u73b0\u7684\u7d22\u5f15<\/span>
\nprint<\/span>(<\/span>fruits.<\/span>index(<\/span>'\u9999\u8549'<\/span>)<\/span>)<\/span> # 1<\/span>
\nprint<\/span>(<\/span>fruits.<\/span>index(<\/span>'\u6a58\u5b50'<\/span>)<\/span>)<\/span> # 2<\/span>
\nprint<\/span>(<\/span>fruits.<\/span>index(<\/span>'\u897f\u74dc'<\/span>)<\/span>)<\/span> # 5<\/span><\/p>\n

# index(x, start)：\u4ecestart\u4f4d\u7f6e\u5f00\u59cb\u627e<\/span>
\nprint<\/span>(<\/span>fruits.<\/span>index(<\/span>'\u9999\u8549'<\/span>,<\/span> 2<\/span>)<\/span>)<\/span> # 4（\u8df3\u8fc7\u7d22\u5f150-1，\u4ece\u7d22\u5f152\u5f00\u59cb\u627e）<\/span><\/p>\n

# index(x, start, end)：\u5728[start, end)\u8303\u56f4\u5185\u627e<\/span>
\nprint<\/span>(<\/span>fruits.<\/span>index(<\/span>'\u9999\u8549'<\/span>,<\/span> 1<\/span>,<\/span> 3<\/span>)<\/span>)<\/span> # 1（\u5728\u7d22\u5f151-2\u8303\u56f4\u5185\u627e\u5230\u4e86）<\/span>
\n# print(fruits.index('\u9999\u8549', 2, 4)) # ValueError（\u5728\u7d22\u5f152-3\u8303\u56f4\u5185\u6ca1\u6709）<\/span><\/p>\n

# \u5143\u7d20\u4e0d\u5b58\u5728\u65f6\u629b\u51faValueError<\/span>
\ntry<\/span>:<\/span>
\n fruits.<\/span>index(<\/span>'\u67e0\u6aac'<\/span>)<\/span>
\nexcept<\/span> ValueError as<\/span> e:<\/span>
\n print<\/span>(<\/span>f'\u9519\u8bef：<\/span>{<\/span>e}<\/span><\/span>'<\/span><\/span>)<\/span> # '\u67e0\u6aac' is not in list<\/span><\/p>\n

2.2 \u5b89\u5168\u7684\u67e5\u627e\u65b9\u5f0f<\/h4>\n

# \u65b9\u5f0f\u4e00：try\/except\u5305\u88c5<\/span>
\ndef<\/span> safe_index<\/span>(<\/span>lst,<\/span> value,<\/span> default=<\/span>–<\/span>1<\/span>)<\/span>:<\/span>
\n """\u5b89\u5168\u67e5\u627e，\u627e\u4e0d\u5230\u8fd4\u56de\u9ed8\u8ba4\u503c"""<\/span>
\n try<\/span>:<\/span>
\n return<\/span> lst.<\/span>index(<\/span>value)<\/span>
\n except<\/span> ValueError:<\/span>
\n return<\/span> default<\/p>\n

fruits =<\/span> [<\/span>'\u82f9\u679c'<\/span>,<\/span> '\u9999\u8549'<\/span>,<\/span> '\u6a58\u5b50'<\/span>]<\/span>
\nprint<\/span>(<\/span>safe_index(<\/span>fruits,<\/span> '\u9999\u8549'<\/span>)<\/span>)<\/span> # 1<\/span>
\nprint<\/span>(<\/span>safe_index(<\/span>fruits,<\/span> '\u67e0\u6aac'<\/span>)<\/span>)<\/span> # -1<\/span><\/p>\n

# \u65b9\u5f0f\u4e8c：\u7528in\u5148\u5224\u65ad（\u4f46\u4f1a\u904d\u5386\u4e24\u6b21）<\/span>
\ndef<\/span> safe_index_v2<\/span>(<\/span>lst,<\/span> value,<\/span> default=<\/span>–<\/span>1<\/span>)<\/span>:<\/span>
\n if<\/span> value in<\/span> lst:<\/span>
\n return<\/span> lst.<\/span>index(<\/span>value)<\/span>
\n return<\/span> default<\/p>\n

# \u65b9\u5f0f\u4e09：\u7528enumerate\u624b\u52a8\u67e5\u627e（\u652f\u6301\u66f4\u590d\u6742\u7684\u6761\u4ef6）<\/span>
\ndef<\/span> find_first<\/span>(<\/span>lst,<\/span> predicate)<\/span>:<\/span>
\n """\u67e5\u627e\u7b2c\u4e00\u4e2a\u6ee1\u8db3\u6761\u4ef6\u7684\u5143\u7d20\u7684\u7d22\u5f15\u548c\u503c"""<\/span>
\n for<\/span> i,<\/span> item in<\/span> enumerate<\/span>(<\/span>lst)<\/span>:<\/span>
\n if<\/span> predicate(<\/span>item)<\/span>:<\/span>
\n return<\/span> i,<\/span> item
\n return<\/span> –<\/span>1<\/span>,<\/span> None<\/span><\/p>\n

nums =<\/span> [<\/span>3<\/span>,<\/span> 7<\/span>,<\/span> 2<\/span>,<\/span> 9<\/span>,<\/span> 4<\/span>,<\/span> 6<\/span>]<\/span>
\nidx,<\/span> val =<\/span> find_first(<\/span>nums,<\/span> lambda<\/span> x:<\/span> x ><\/span> 5<\/span>)<\/span>
\nprint<\/span>(<\/span>f'\u7b2c\u4e00\u4e2a\u5927\u4e8e5\u7684\u6570：nums[<\/span>{<\/span>idx}<\/span><\/span>] = <\/span>{<\/span>val}<\/span><\/span>'<\/span><\/span>)<\/span> # nums[1] = 7<\/span><\/p>\n

# \u65b9\u5f0f\u56db：\u67e5\u627e\u6240\u6709\u5339\u914d\u7684\u4f4d\u7f6e<\/span>
\ndef<\/span> find_all<\/span>(<\/span>lst,<\/span> value)<\/span>:<\/span>
\n """\u627e\u51fa\u6240\u6709\u5339\u914d\u503c\u7684\u7d22\u5f15"""<\/span>
\n return<\/span> [<\/span>i for<\/span> i,<\/span> x in<\/span> enumerate<\/span>(<\/span>lst)<\/span> if<\/span> x ==<\/span> value]<\/span><\/p>\n

data =<\/span> [<\/span>1<\/span>,<\/span> 3<\/span>,<\/span> 5<\/span>,<\/span> 3<\/span>,<\/span> 7<\/span>,<\/span> 3<\/span>,<\/span> 9<\/span>]<\/span>
\nprint<\/span>(<\/span>find_all(<\/span>data,<\/span> 3<\/span>)<\/span>)<\/span> # [1, 3, 5]<\/span><\/p>\n

2.3 count()\u2014\u2014\u7edf\u8ba1\u51fa\u73b0\u6b21\u6570<\/h4>\n

nums =<\/span> [<\/span>1<\/span>,<\/span> 2<\/span>,<\/span> 3<\/span>,<\/span> 2<\/span>,<\/span> 1<\/span>,<\/span> 2<\/span>,<\/span> 3<\/span>,<\/span> 2<\/span>,<\/span> 1<\/span>,<\/span> 2<\/span>]<\/span><\/p>\n

# count(x)：\u7edf\u8ba1x\u51fa\u73b0\u7684\u6b21\u6570<\/span>
\nprint<\/span>(<\/span>nums.<\/span>count(<\/span>1<\/span>)<\/span>)<\/span> # 3<\/span>
\nprint<\/span>(<\/span>nums.<\/span>count(<\/span>2<\/span>)<\/span>)<\/span> # 5<\/span>
\nprint<\/span>(<\/span>nums.<\/span>count(<\/span>3<\/span>)<\/span>)<\/span> # 2<\/span>
\nprint<\/span>(<\/span>nums.<\/span>count(<\/span>999<\/span>)<\/span>)<\/span> # 0（\u4e0d\u5b58\u5728\u7684\u5143\u7d20\u4e0d\u4f1a\u62a5\u9519，\u8fd4\u56de0）<\/span><\/p>\n

# count \u7684\u5b9e\u7528\u573a\u666f<\/span>
\n# \u627e\u51fa\u73b0\u6b21\u6570\u6700\u591a\u7684\u5143\u7d20（\u4f17\u6570）<\/span>
\ndef<\/span> mode<\/span>(<\/span>lst)<\/span>:<\/span>
\n """\u627e\u51fa\u5217\u8868\u4e2d\u51fa\u73b0\u6b21\u6570\u6700\u591a\u7684\u5143\u7d20"""<\/span>
\n if<\/span> not<\/span> lst:<\/span>
\n return<\/span> None<\/span>
\n return<\/span> max<\/span>(<\/span>set<\/span>(<\/span>lst)<\/span>,<\/span> key=<\/span>lst.<\/span>count)<\/span><\/p>\n

print<\/span>(<\/span>mode(<\/span>nums)<\/span>)<\/span> # 2（\u51fa\u73b0\u4e865\u6b21）<\/span><\/p>\n

# \u68c0\u67e5\u662f\u5426\u6709\u91cd\u590d\u5143\u7d20<\/span>
\ndef<\/span> has_duplicates<\/span>(<\/span>lst)<\/span>:<\/span>
\n """\u68c0\u67e5\u5217\u8868\u662f\u5426\u6709\u91cd\u590d\u5143\u7d20"""<\/span>
\n return<\/span> len<\/span>(<\/span>lst)<\/span> !=<\/span> len<\/span>(<\/span>set<\/span>(<\/span>lst)<\/span>)<\/span><\/p>\n

print<\/span>(<\/span>has_duplicates(<\/span>[<\/span>1<\/span>,<\/span> 2<\/span>,<\/span> 3<\/span>,<\/span> 4<\/span>]<\/span>)<\/span>)<\/span> # False<\/span>
\nprint<\/span>(<\/span>has_duplicates(<\/span>[<\/span>1<\/span>,<\/span> 2<\/span>,<\/span> 3<\/span>,<\/span> 2<\/span>]<\/span>)<\/span>)<\/span> # True<\/span><\/p>\n

# \u7edf\u8ba1\u6240\u6709\u5143\u7d20\u7684\u9891\u7387<\/span>
\nfrom<\/span> collections import<\/span> Counter
\ncounter =<\/span> Counter(<\/span>nums)<\/span>
\nprint<\/span>(<\/span>counter)<\/span> # Counter({2: 5, 1: 3, 3: 2})<\/span>
\nprint<\/span>(<\/span>counter.<\/span>most_common(<\/span>2<\/span>)<\/span>)<\/span> # [(2, 5), (1, 3)]（\u51fa\u73b0\u6700\u591a\u7684\u524d2\u4e2a）<\/span><\/p>\n

\u4e09\u3001\u6392\u5e8f\u2014\u2014sort() vs sorted()<\/h3>\n

3.1 sort()\u2014\u2014\u539f\u5730\u6392\u5e8f<\/h4>\n

# sort() \u539f\u5730\u4fee\u6539\u5217\u8868，\u4e0d\u8fd4\u56de\u65b0\u5217\u8868<\/span>
\nnums =<\/span> [<\/span>5<\/span>,<\/span> 2<\/span>,<\/span> 8<\/span>,<\/span> 1<\/span>,<\/span> 9<\/span>,<\/span> 3<\/span>]<\/span><\/p>\n

# \u9ed8\u8ba4\u5347\u5e8f\u6392\u5e8f<\/span>
\nnums.<\/span>sort(<\/span>)<\/span>
\nprint<\/span>(<\/span>nums)<\/span> # [1, 2, 3, 5, 8, 9]<\/span><\/p>\n

# reverse=True \u964d\u5e8f\u6392\u5e8f<\/span>
\nnums.<\/span>sort(<\/span>reverse=<\/span>True<\/span>)<\/span>
\nprint<\/span>(<\/span>nums)<\/span> # [9, 8, 5, 3, 2, 1]<\/span><\/p>\n

# \u5b57\u7b26\u4e32\u6392\u5e8f（\u6309\u5b57\u5178\u5e8f）<\/span>
\nwords =<\/span> [<\/span>'banana'<\/span>,<\/span> 'apple'<\/span>,<\/span> 'cherry'<\/span>,<\/span> 'date'<\/span>]<\/span>
\nwords.<\/span>sort(<\/span>)<\/span>
\nprint<\/span>(<\/span>words)<\/span> # ['apple', 'banana', 'cherry', 'date']<\/span><\/p>\n

# \u5b57\u7b26\u4e32\u6309\u957f\u5ea6\u6392\u5e8f（\u4f7f\u7528key\u53c2\u6570）<\/span>
\nwords.<\/span>sort(<\/span>key=<\/span>len<\/span>)<\/span>
\nprint<\/span>(<\/span>words)<\/span> # ['date', 'apple', 'banana', 'cherry']<\/span><\/p>\n

# \u6309\u957f\u5ea6\u964d\u5e8f<\/span>
\nwords.<\/span>sort(<\/span>key=<\/span>len<\/span>,<\/span> reverse=<\/span>True<\/span>)<\/span>
\nprint<\/span>(<\/span>words)<\/span> # ['banana', 'cherry', 'apple', 'date']<\/span><\/p>\n

# sort() \u8fd4\u56de None<\/span>
\nresult =<\/span> nums.<\/span>sort(<\/span>)<\/span>
\nprint<\/span>(<\/span>result)<\/span> # None（\u91cd\u8981：sort()\u6ca1\u6709\u8fd4\u56de\u503c）<\/span><\/p>\n

\u26a0\ufe0f sort() \u8fd4\u56de None，\u8fd9\u662f\u4e00\u4e2a\u5e38\u89c1\u7684\u5751\u3002\u4e0d\u8981\u5728\u94fe\u5f0f\u8c03\u7528\u4e2d\u4f7f\u7528\u5b83，\u4e5f\u4e0d\u8981\u628a\u5b83\u7684\u8fd4\u56de\u503c\u8d4b\u7ed9\u53d8\u91cf\u3002<\/p>\n

3.2 sorted()\u2014\u2014\u8fd4\u56de\u65b0\u5217\u8868<\/h4>\n

# sorted() \u4e0d\u4f1a\u4fee\u6539\u539f\u5217\u8868，\u8fd4\u56de\u4e00\u4e2a\u65b0\u7684\u6392\u5e8f\u540e\u7684\u5217\u8868<\/span>
\nnums =<\/span> [<\/span>5<\/span>,<\/span> 2<\/span>,<\/span> 8<\/span>,<\/span> 1<\/span>,<\/span> 9<\/span>,<\/span> 3<\/span>]<\/span><\/p>\n

# \u5347\u5e8f<\/span>
\nsorted_nums =<\/span> sorted<\/span>(<\/span>nums)<\/span>
\nprint<\/span>(<\/span>f'\u539f\u5217\u8868: <\/span>{<\/span>nums}<\/span><\/span>'<\/span><\/span>)<\/span> # [5, 2, 8, 1, 9, 3]（\u4e0d\u53d8）<\/span>
\nprint<\/span>(<\/span>f'\u6392\u5e8f\u540e: <\/span>{<\/span>sorted_nums}<\/span><\/span>'<\/span><\/span>)<\/span> # [1, 2, 3, 5, 8, 9]<\/span><\/p>\n

# \u964d\u5e8f<\/span>
\nsorted_desc =<\/span> sorted<\/span>(<\/span>nums,<\/span> reverse=<\/span>True<\/span>)<\/span>
\nprint<\/span>(<\/span>sorted_desc)<\/span> # [9, 8, 5, 3, 2, 1]<\/span><\/p>\n

# sorted() \u662f\u4e00\u4e2a\u5185\u7f6e\u51fd\u6570，\u53ef\u4ee5\u7528\u4e8e\u4efb\u4f55\u53ef\u8fed\u4ee3\u5bf9\u8c61<\/span>
\nprint<\/span>(<\/span>sorted<\/span>(<\/span>'python'<\/span>)<\/span>)<\/span> # ['h', 'n', 'o', 'p', 't', 'y']<\/span>
\nprint<\/span>(<\/span>sorted<\/span>(<\/span>{<\/span>3<\/span>,<\/span> 1<\/span>,<\/span> 4<\/span>,<\/span> 1<\/span>,<\/span> 5<\/span>}<\/span>)<\/span>)<\/span> # [1, 3, 4, 5]（\u96c6\u5408\u2192\u6392\u597d\u5e8f\u7684\u5217\u8868）<\/span>
\nprint<\/span>(<\/span>sorted<\/span>(<\/span>(<\/span>3<\/span>,<\/span> 1<\/span>,<\/span> 4<\/span>,<\/span> 2<\/span>)<\/span>)<\/span>)<\/span> # [1, 2, 3, 4]（\u5143\u7ec4\u2192\u6392\u597d\u5e8f\u7684\u5217\u8868）<\/span><\/p>\n

# sorted\u914d\u5408\u751f\u6210\u5668<\/span>
\ngen =<\/span> (<\/span>x **<\/span> 2<\/span> for<\/span> x in<\/span> range<\/span>(<\/span>10<\/span>,<\/span> 0<\/span>,<\/span> –<\/span>1<\/span>)<\/span>)<\/span>
\nprint<\/span>(<\/span>sorted<\/span>(<\/span>gen)<\/span>)<\/span> # [1, 4, 9, 16, 25, 36, 49, 64, 81, 100]<\/span><\/p>\n

3.3 sort() vs sorted() \u7684\u9009\u62e9<\/h4>\n

# \u9009\u62e9\u6307\u5357：<\/span><\/p>\n

# \u9700\u8981\u4fdd\u7559\u539f\u5217\u8868 \u2192 sorted()<\/span>
\noriginal =<\/span> [<\/span>3<\/span>,<\/span> 1<\/span>,<\/span> 4<\/span>,<\/span> 1<\/span>,<\/span> 5<\/span>]<\/span>
\nresult =<\/span> sorted<\/span>(<\/span>original)<\/span>
\n# original \u4ecd\u7136\u662f [3, 1, 4, 1, 5]<\/span><\/p>\n

# \u4e0d\u9700\u8981\u4fdd\u7559\u539f\u5217\u8868，\u53ea\u9700\u6392\u5e8f\u540e\u7684\u7ed3\u679c \u2192 sort()（\u7701\u5185\u5b58）<\/span>
\ndata =<\/span> [<\/span>3<\/span>,<\/span> 1<\/span>,<\/span> 4<\/span>,<\/span> 1<\/span>,<\/span> 5<\/span>]<\/span>
\ndata.<\/span>sort(<\/span>)<\/span> # data \u73b0\u5728\u662f [1, 1, 3, 4, 5]<\/span><\/p>\n

# \u9700\u8981\u5bf9\u975e\u5217\u8868\u7684\u53ef\u8fed\u4ee3\u5bf9\u8c61\u6392\u5e8f \u2192 sorted()（\u552f\u4e00\u9009\u62e9）<\/span>
\ntuple_data =<\/span> (<\/span>3<\/span>,<\/span> 1<\/span>,<\/span> 4<\/span>,<\/span> 1<\/span>,<\/span> 5<\/span>)<\/span>
\nsorted_tuple =<\/span> sorted<\/span>(<\/span>tuple_data)<\/span> # tuple\u6ca1\u6709sort\u65b9\u6cd5！<\/span><\/p>\n

# \u9700\u8981\u5728\u94fe\u5f0f\u64cd\u4f5c\u4e2d\u4f7f\u7528 \u2192 sorted()<\/span>
\n# sorted\u53ef\u4ee5\u5d4c\u5728\u8868\u8fbe\u5f0f\u4e2d<\/span>
\nresult =<\/span> ','<\/span>.<\/span>join(<\/span>sorted<\/span>(<\/span>set<\/span>(<\/span>names)<\/span>)<\/span>)<\/span><\/p>\n

\u56db\u3001key\u53c2\u6570\u2014\u2014\u81ea\u5b9a\u4e49\u6392\u5e8f\u7684\u7075\u9b42<\/h3>\n

4.1 key\u53c2\u6570\u7684\u57fa\u672c\u7528\u6cd5<\/h4>\n

# key\u53c2\u6570\u63a5\u53d7\u4e00\u4e2a\u51fd\u6570，\u6392\u5e8f\u65f6\u7528\u8be5\u51fd\u6570\u7684\u8fd4\u56de\u503c\u6765\u6bd4\u8f83<\/span>
\n# \u800c\u4e0d\u662f\u76f4\u63a5\u6bd4\u8f83\u5143\u7d20\u672c\u8eab<\/span><\/p>\n

# \u6309\u5b57\u7b26\u4e32\u957f\u5ea6\u6392\u5e8f<\/span>
\nwords =<\/span> [<\/span>'a'<\/span>,<\/span> 'abcde'<\/span>,<\/span> 'abc'<\/span>,<\/span> 'ab'<\/span>,<\/span> 'abcd'<\/span>]<\/span>
\nwords.<\/span>sort(<\/span>key=<\/span>len<\/span>)<\/span>
\nprint<\/span>(<\/span>words)<\/span> # ['a', 'ab', 'abc', 'abcd', 'abcde']<\/span><\/p>\n

# \u6309\u7edd\u5bf9\u503c\u6392\u5e8f<\/span>
\nnums =<\/span> [<\/span>–<\/span>5<\/span>,<\/span> 3<\/span>,<\/span> –<\/span>1<\/span>,<\/span> 4<\/span>,<\/span> –<\/span>2<\/span>]<\/span>
\nnums.<\/span>sort(<\/span>key=<\/span>abs<\/span>)<\/span>
\nprint<\/span>(<\/span>nums)<\/span> # [-1, -2, 3, 4, -5]（\u6309\u7edd\u5bf9\u503c=1,2,3,4,5\u6392\u5e8f）<\/span><\/p>\n

# \u6309\u5b57\u6bcd\u6392\u5e8f（\u5ffd\u7565\u5927\u5c0f\u5199）<\/span>
\nfruits =<\/span> [<\/span>'apple'<\/span>,<\/span> 'Banana'<\/span>,<\/span> 'cherry'<\/span>,<\/span> 'Apple'<\/span>]<\/span>
\nfruits.<\/span>sort(<\/span>key=<\/span>str<\/span>.<\/span>lower)<\/span>
\nprint<\/span>(<\/span>fruits)<\/span> # ['apple', 'Apple', 'Banana', 'cherry']<\/span><\/p>\n

# \u6309\u5b57\u7b26\u4e32\u4e2d\u6700\u540e\u4e00\u4e2a\u5b57\u7b26\u6392\u5e8f<\/span>
\nwords =<\/span> [<\/span>'hello'<\/span>,<\/span> 'world'<\/span>,<\/span> 'python'<\/span>,<\/span> 'java'<\/span>]<\/span>
\nwords.<\/span>sort(<\/span>key=<\/span>lambda<\/span> w:<\/span> w[<\/span>–<\/span>1<\/span>]<\/span>)<\/span>
\nprint<\/span>(<\/span>words)<\/span> # ['java', 'world', 'python', 'hello']<\/span>
\n# \u6309\u6700\u540e\u4e00\u4e2a\u5b57\u6bcd\u6392: a < d < n < o<\/span><\/p>\n

4.2 lambda \u5728key\u4e2d\u7684\u5e94\u7528<\/h4>\n

# lambda\u662fkey\u53c2\u6570\u7684\u7edd\u4f73\u642d\u6863<\/span><\/p>\n

# \u6309\u7edd\u5bf9\u503c\u6392\u5e8f<\/span>
\nnums =<\/span> [<\/span>–<\/span>5<\/span>,<\/span> 3<\/span>,<\/span> –<\/span>10<\/span>,<\/span> 4<\/span>,<\/span> –<\/span>2<\/span>]<\/span>
\nnums.<\/span>sort(<\/span>key=<\/span>lambda<\/span> x:<\/span> abs<\/span>(<\/span>x)<\/span>)<\/span>
\nprint<\/span>(<\/span>nums)<\/span> # [-2, 3, 4, -5, -10]<\/span><\/p>\n

# \u6309\u5143\u7ec4\u4e2d\u7b2c\u4e8c\u4e2a\u5143\u7d20\u6392\u5e8f<\/span>
\npairs =<\/span> [<\/span>(<\/span>1<\/span>,<\/span> 3<\/span>)<\/span>,<\/span> (<\/span>2<\/span>,<\/span> 1<\/span>)<\/span>,<\/span> (<\/span>4<\/span>,<\/span> 2<\/span>)<\/span>,<\/span> (<\/span>3<\/span>,<\/span> 4<\/span>)<\/span>]<\/span>
\npairs.<\/span>sort(<\/span>key=<\/span>lambda<\/span> p:<\/span> p[<\/span>1<\/span>]<\/span>)<\/span>
\nprint<\/span>(<\/span>pairs)<\/span> # [(2, 1), (4, 2), (1, 3), (3, 4)]<\/span><\/p>\n

# \u6309\u5b57\u5178\u4e2d\u67d0\u4e2a\u5b57\u6bb5\u6392\u5e8f<\/span>
\nusers =<\/span> [<\/span>
\n {<\/span>'name'<\/span>:<\/span> '\u5c0f\u660e'<\/span>,<\/span> 'age'<\/span>:<\/span> 25<\/span>}<\/span>,<\/span>
\n {<\/span>'name'<\/span>:<\/span> '\u5c0f\u7ea2'<\/span>,<\/span> 'age'<\/span>:<\/span> 23<\/span>}<\/span>,<\/span>
\n {<\/span>'name'<\/span>:<\/span> '\u5c0f\u521a'<\/span>,<\/span> 'age'<\/span>:<\/span> 26<\/span>}<\/span>,<\/span>
\n]<\/span>
\nusers.<\/span>sort(<\/span>key=<\/span>lambda<\/span> u:<\/span> u[<\/span>'age'<\/span>]<\/span>)<\/span>
\nprint<\/span>(<\/span>users)<\/span>
\n# [{'name': '\u5c0f\u7ea2', 'age': 23}, {'name': '\u5c0f\u660e', 'age': 25}, {'name': '\u5c0f\u521a', 'age': 26}]<\/span><\/p>\n

# \u6309\u591a\u4e2a\u5b57\u6bb5\u6392\u5e8f\u2014\u2014\u8fd4\u56de\u5143\u7ec4\u5b9e\u73b0\u591a\u7ea7\u6392\u5e8f<\/span>
\nstudents =<\/span> [<\/span>
\n (<\/span>'\u5c0f\u660e'<\/span>,<\/span> 85<\/span>,<\/span> 2<\/span>)<\/span>,<\/span>
\n (<\/span>'\u5c0f\u7ea2'<\/span>,<\/span> 92<\/span>,<\/span> 1<\/span>)<\/span>,<\/span>
\n (<\/span>'\u5c0f\u521a'<\/span>,<\/span> 85<\/span>,<\/span> 1<\/span>)<\/span>,<\/span>
\n (<\/span>'\u5c0f\u674e'<\/span>,<\/span> 92<\/span>,<\/span> 2<\/span>)<\/span>,<\/span>
\n]<\/span>
\n# \u5148\u6309\u6210\u7ee9\u964d\u5e8f，\u518d\u6309\u73ed\u7ea7\u5347\u5e8f<\/span>
\nstudents.<\/span>sort(<\/span>key=<\/span>lambda<\/span> s:<\/span> (<\/span>–<\/span>s[<\/span>1<\/span>]<\/span>,<\/span> s[<\/span>2<\/span>]<\/span>)<\/span>)<\/span>
\nprint<\/span>(<\/span>students)<\/span>
\n# [('\u5c0f\u7ea2', 92, 1), ('\u5c0f\u674e', 92, 2), ('\u5c0f\u660e', 85, 2), ('\u5c0f\u521a', 85, 1)]<\/span><\/p>\n

# \u66f4\u590d\u6742：\u6309\u6761\u4ef6\u6392\u5e8f<\/span>
\n# \u5c06\u5076\u6570\u6392\u524d\u9762，\u5947\u6570\u6392\u540e\u9762，\u5404\u81ea\u5185\u90e8\u5347\u5e8f<\/span>
\nnums =<\/span> [<\/span>1<\/span>,<\/span> 2<\/span>,<\/span> 3<\/span>,<\/span> 4<\/span>,<\/span> 5<\/span>,<\/span> 6<\/span>,<\/span> 7<\/span>,<\/span> 8<\/span>,<\/span> 9<\/span>]<\/span>
\nnums.<\/span>sort(<\/span>key=<\/span>lambda<\/span> x:<\/span> (<\/span>x %<\/span> 2<\/span>,<\/span> x)<\/span>)<\/span>
\nprint<\/span>(<\/span>nums)<\/span> # [2, 4, 6, 8, 1, 3, 5, 7, 9]<\/span>
\n# \u6392\u5e8f\u952e\u662f\u5143\u7ec4 (x%2, x)<\/span>
\n# \u5076\u6570: (0, \u5076\u6570) \u5947\u6570: (1, \u5947\u6570)<\/span>
\n# 0<1 \u6240\u4ee5\u5076\u6570\u6392\u5728\u5947\u6570\u524d\u9762<\/span>
\n# \u7ec4\u5185\u6309x\u672c\u8eab\u6392\u5e8f<\/span><\/p>\n

4.3 \u4f7f\u7528operator\u6a21\u5757\u66ff\u4ee3lambda<\/h4>\n

from<\/span> operator import<\/span> itemgetter,<\/span> attrgetter,<\/span> methodcaller<\/p>\n

# itemgetter：\u7b49\u4ef7\u4e8e lambda x: x[n]<\/span>
\n# \u4f46\u6027\u80fd\u66f4\u597d（\u7eafC\u5b9e\u73b0）<\/span><\/p>\n

students =<\/span> [<\/span>
\n (<\/span>'\u5c0f\u660e'<\/span>,<\/span> 85<\/span>,<\/span> 'A\u73ed'<\/span>)<\/span>,<\/span>
\n (<\/span>'\u5c0f\u7ea2'<\/span>,<\/span> 92<\/span>,<\/span> 'B\u73ed'<\/span>)<\/span>,<\/span>
\n (<\/span>'\u5c0f\u521a'<\/span>,<\/span> 78<\/span>,<\/span> 'A\u73ed'<\/span>)<\/span>,<\/span>
\n]<\/span><\/p>\n

# \u6309\u6210\u7ee9\u6392\u5e8f（\u5143\u7ec4\u7684\u7b2c1\u4e2a\u7d22\u5f15）<\/span>
\nstudents.<\/span>sort(<\/span>key=<\/span>itemgetter(<\/span>1<\/span>)<\/span>)<\/span>
\nprint<\/span>(<\/span>students)<\/span> # [('\u5c0f\u521a', 78, 'A\u73ed'), ('\u5c0f\u660e', 85, 'A\u73ed'), ('\u5c0f\u7ea2', 92, 'B\u73ed')]<\/span><\/p>\n

# \u591a\u7ea7\u6392\u5e8f：\u5148\u6309\u73ed\u7ea7(2)，\u518d\u6309\u6210\u7ee9(1)<\/span>
\nstudents.<\/span>sort(<\/span>key=<\/span>itemgetter(<\/span>2<\/span>,<\/span> 1<\/span>)<\/span>)<\/span>
\nprint<\/span>(<\/span>students)<\/span>
\n# [('\u5c0f\u521a', 78, 'A\u73ed'), ('\u5c0f\u660e', 85, 'A\u73ed'), ('\u5c0f\u7ea2', 92, 'B\u73ed')]<\/span><\/p>\n

# attrgetter：\u6309\u5bf9\u8c61\u5c5e\u6027\u6392\u5e8f<\/span>
\nclass<\/span> Student<\/span>:<\/span>
\n def<\/span> __init__<\/span>(<\/span>self,<\/span> name,<\/span> score)<\/span>:<\/span>
\n self.<\/span>name =<\/span> name
\n self.<\/span>score =<\/span> score<\/p>\n

def<\/span> __repr__<\/span>(<\/span>self)<\/span>:<\/span>
\n return<\/span> f'Student(<\/span>{<\/span>self.<\/span>name}<\/span><\/span>, <\/span>{<\/span>self.<\/span>score}<\/span><\/span>)'<\/span><\/span><\/p>\n

students =<\/span> [<\/span>
\n Student(<\/span>'\u5c0f\u660e'<\/span>,<\/span> 85<\/span>)<\/span>,<\/span>
\n Student(<\/span>'\u5c0f\u7ea2'<\/span>,<\/span> 92<\/span>)<\/span>,<\/span>
\n Student(<\/span>'\u5c0f\u521a'<\/span>,<\/span> 78<\/span>)<\/span>,<\/span>
\n]<\/span>
\nstudents.<\/span>sort(<\/span>key=<\/span>attrgetter(<\/span>'score'<\/span>)<\/span>)<\/span>
\nprint<\/span>(<\/span>students)<\/span>
\n# [Student(\u5c0f\u521a, 78), Student(\u5c0f\u660e, 85), Student(\u5c0f\u7ea2, 92)]<\/span><\/p>\n

# methodcaller：\u6309\u65b9\u6cd5\u8c03\u7528\u7ed3\u679c\u6392\u5e8f<\/span>
\nwords =<\/span> [<\/span>'hello'<\/span>,<\/span> 'World'<\/span>,<\/span> 'PYTHON'<\/span>,<\/span> 'Code'<\/span>]<\/span>
\nwords.<\/span>sort(<\/span>key=<\/span>methodcaller(<\/span>'lower'<\/span>)<\/span>)<\/span>
\nprint<\/span>(<\/span>words)<\/span> # ['Code', 'hello', 'PYTHON', 'World']<\/span><\/p>\n

💡 \u6027\u80fd\u5efa\u8bae：\u5bf9\u4e8e\u7b80\u5355\u7684\u5b57\u6bb5\u8bbf\u95ee（\u5982 x[1] \u6216 x.name），\u4f18\u5148\u7528 itemgetter \u6216 attrgetter \u800c\u4e0d\u662f lambda\u2014\u2014\u5b83\u4eec\u5728C\u5c42\u9762\u5b9e\u73b0，\u901a\u5e38\u66f4\u5feb\u3002<\/p>\n

4.4 \u7a33\u5b9a\u6392\u5e8f\u4e0e\u591a\u7ea7\u6392\u5e8f<\/h4>\n

# Python\u7684sort\u662f\u7a33\u5b9a\u7684（Timsort\u7b97\u6cd5）<\/span>
\n# \u7a33\u5b9a\u6392\u5e8f\u610f\u5473\u7740：\u76f8\u7b49\u5143\u7d20\u7684\u76f8\u5bf9\u987a\u5e8f\u5728\u6392\u5e8f\u540e\u4fdd\u6301\u4e0d\u53d8<\/span><\/p>\n

# \u5229\u7528\u7a33\u5b9a\u6027\u5b9e\u73b0\u591a\u7ea7\u6392\u5e8f<\/span>
\ndata =<\/span> [<\/span>
\n (<\/span>'\u5c0f\u660e'<\/span>,<\/span> 'A\u73ed'<\/span>,<\/span> 85<\/span>)<\/span>,<\/span>
\n (<\/span>'\u5c0f\u7ea2'<\/span>,<\/span> 'B\u73ed'<\/span>,<\/span> 92<\/span>)<\/span>,<\/span>
\n (<\/span>'\u5c0f\u521a'<\/span>,<\/span> 'A\u73ed'<\/span>,<\/span> 78<\/span>)<\/span>,<\/span>
\n (<\/span>'\u5c0f\u674e'<\/span>,<\/span> 'B\u73ed'<\/span>,<\/span> 88<\/span>)<\/span>,<\/span>
\n (<\/span>'\u5c0f\u738b'<\/span>,<\/span> 'A\u73ed'<\/span>,<\/span> 95<\/span>)<\/span>,<\/span>
\n]<\/span><\/p>\n

# \u9700\u6c42：\u5148\u6309\u73ed\u7ea7\u6392\u5e8f，\u518d\u6309\u6210\u7ee9\u964d\u5e8f<\/span>
\n# \u7b56\u7565：\u4ece\u6700\u4e0d\u91cd\u8981\u7684\u6761\u4ef6\u5f00\u59cb\u6392\u5e8f<\/span><\/p>\n

# \u5148\u6309\u6210\u7ee9\u964d\u5e8f（\u6b21\u8981\u6761\u4ef6）<\/span>
\ndata.<\/span>sort(<\/span>key=<\/span>lambda<\/span> x:<\/span> x[<\/span>2<\/span>]<\/span>,<\/span> reverse=<\/span>True<\/span>)<\/span>
\n# \u518d\u6309\u73ed\u7ea7\u6392\u5e8f（\u4e3b\u8981\u6761\u4ef6）\u2014\u2014\u7a33\u5b9a\u6027\u4fdd\u8bc1\u540c\u73ed\u7ea7\u5185\u6210\u7ee9\u987a\u5e8f\u4e0d\u53d8<\/span>
\ndata.<\/span>sort(<\/span>key=<\/span>lambda<\/span> x:<\/span> x[<\/span>1<\/span>]<\/span>)<\/span><\/p>\n

for<\/span> student in<\/span> data:<\/span>
\n print<\/span>(<\/span>student)<\/span>
\n# ('\u5c0f\u738b', 'A\u73ed', 95)<\/span>
\n# ('\u5c0f\u660e', 'A\u73ed', 85)<\/span>
\n# ('\u5c0f\u521a', 'A\u73ed', 78)<\/span>
\n# ('\u5c0f\u7ea2', 'B\u73ed', 92)<\/span>
\n# ('\u5c0f\u674e', 'B\u73ed', 88)<\/span><\/p>\n

# \u540c\u6837\u7684\u7ed3\u679c\u4e5f\u53ef\u4ee5\u7528\u5143\u7ec4key\u4e00\u6b21\u5b8c\u6210<\/span>
\ndata2 =<\/span> [<\/span>
\n (<\/span>'\u5c0f\u660e'<\/span>,<\/span> 'A\u73ed'<\/span>,<\/span> 85<\/span>)<\/span>,<\/span>
\n (<\/span>'\u5c0f\u7ea2'<\/span>,<\/span> 'B\u73ed'<\/span>,<\/span> 92<\/span>)<\/span>,<\/span>
\n (<\/span>'\u5c0f\u521a'<\/span>,<\/span> 'A\u73ed'<\/span>,<\/span> 78<\/span>)<\/span>,<\/span>
\n (<\/span>'\u5c0f\u674e'<\/span>,<\/span> 'B\u73ed'<\/span>,<\/span> 88<\/span>)<\/span>,<\/span>
\n (<\/span>'\u5c0f\u738b'<\/span>,<\/span> 'A\u73ed'<\/span>,<\/span> 95<\/span>)<\/span>,<\/span>
\n]<\/span>
\ndata2.<\/span>sort(<\/span>key=<\/span>lambda<\/span> x:<\/span> (<\/span>x[<\/span>1<\/span>]<\/span>,<\/span> –<\/span>x[<\/span>2<\/span>]<\/span>)<\/span>)<\/span>
\nprint<\/span>(<\/span>data2)<\/span>
\n# \u7ed3\u679c\u76f8\u540c<\/span><\/p>\n

\u4e94\u3001\u53cd\u8f6c\u2014\u2014reverse()\u3001reversed() \u548c [::-1]<\/h3>\n

5.1 reverse()\u2014\u2014\u539f\u5730\u53cd\u8f6c<\/h4>\n

# reverse() \u539f\u5730\u53cd\u8f6c\u5217\u8868，\u4e0d\u8fd4\u56de\u65b0\u5217\u8868<\/span>
\nnums =<\/span> [<\/span>1<\/span>,<\/span> 2<\/span>,<\/span> 3<\/span>,<\/span> 4<\/span>,<\/span> 5<\/span>]<\/span>
\nnums.<\/span>reverse(<\/span>)<\/span>
\nprint<\/span>(<\/span>nums)<\/span> # [5, 4, 3, 2, 1]<\/span><\/p>\n

# \u5b57\u7b26\u4e32\u5217\u8868<\/span>
\nfruits =<\/span> [<\/span>'\u82f9\u679c'<\/span>,<\/span> '\u9999\u8549'<\/span>,<\/span> '\u6a58\u5b50'<\/span>]<\/span>
\nfruits.<\/span>reverse(<\/span>)<\/span>
\nprint<\/span>(<\/span>fruits)<\/span> # ['\u6a58\u5b50', '\u9999\u8549', '\u82f9\u679c']<\/span><\/p>\n

# reverse() \u8fd4\u56de None<\/span>
\nresult =<\/span> [<\/span>1<\/span>,<\/span> 2<\/span>,<\/span> 3<\/span>]<\/span>.<\/span>reverse(<\/span>)<\/span>
\nprint<\/span>(<\/span>result)<\/span> # None<\/span><\/p>\n

5.2 reversed()\u2014\u2014\u8fd4\u56de\u53cd\u5411\u8fed\u4ee3\u5668<\/h4>\n

# reversed() \u4e0d\u4fee\u6539\u539f\u5217\u8868，\u8fd4\u56de\u4e00\u4e2a\u53cd\u5411\u8fed\u4ee3\u5668<\/span>
\nnums =<\/span> [<\/span>1<\/span>,<\/span> 2<\/span>,<\/span> 3<\/span>,<\/span> 4<\/span>,<\/span> 5<\/span>]<\/span><\/p>\n

rev =<\/span> reversed<\/span>(<\/span>nums)<\/span>
\nprint<\/span>(<\/span>rev)<\/span> # <list_reverseiterator object at 0x…><\/span>
\nprint<\/span>(<\/span>type<\/span>(<\/span>rev)<\/span>)<\/span> # <class 'list_reverseiterator'><\/span><\/p>\n

# \u8f6c\u4e3a\u5217\u8868<\/span>
\nprint<\/span>(<\/span>list<\/span>(<\/span>rev)<\/span>)<\/span> # [5, 4, 3, 2, 1]<\/span>
\nprint<\/span>(<\/span>list<\/span>(<\/span>rev)<\/span>)<\/span> # []（\u8fed\u4ee3\u5668\u5df2\u8017\u5c3d！）<\/span><\/p>\n

# \u539f\u5217\u8868\u4e0d\u53d8<\/span>
\nprint<\/span>(<\/span>nums)<\/span> # [1, 2, 3, 4, 5]<\/span><\/p>\n

# reversed() \u5e38\u7528\u4e8e\u53cd\u5411\u904d\u5386<\/span>
\nfor<\/span> num in<\/span> reversed<\/span>(<\/span>nums)<\/span>:<\/span>
\n print<\/span>(<\/span>num,<\/span> end=<\/span>' '<\/span>)<\/span> # 5 4 3 2 1<\/span>
\nprint<\/span>(<\/span>)<\/span><\/p>\n

# reversed() \u4e5f\u9002\u7528\u4e8e\u5176\u4ed6\u5e8f\u5217<\/span>
\nprint<\/span>(<\/span>''<\/span>.<\/span>join(<\/span>reversed<\/span>(<\/span>'hello'<\/span>)<\/span>)<\/span>)<\/span> # olleh<\/span><\/p>\n

5.3 [::-1]\u2014\u2014\u5207\u7247\u53cd\u8f6c<\/h4>\n

# [::-1] \u521b\u5efa\u53cd\u8f6c\u540e\u7684\u65b0\u5217\u8868<\/span>
\nnums =<\/span> [<\/span>1<\/span>,<\/span> 2<\/span>,<\/span> 3<\/span>,<\/span> 4<\/span>,<\/span> 5<\/span>]<\/span>
\nreversed_nums =<\/span> nums[<\/span>:<\/span>:<\/span>–<\/span>1<\/span>]<\/span>
\nprint<\/span>(<\/span>reversed_nums)<\/span> # [5, 4, 3, 2, 1]<\/span>
\nprint<\/span>(<\/span>nums)<\/span> # [1, 2, 3, 4, 5]（\u539f\u5217\u8868\u4e0d\u53d8）<\/span><\/p>\n

# \u4e09\u79cd\u53cd\u8f6c\u65b9\u5f0f\u7684\u5bf9\u6bd4：<\/span>
\nnums =<\/span> [<\/span>1<\/span>,<\/span> 2<\/span>,<\/span> 3<\/span>,<\/span> 4<\/span>,<\/span> 5<\/span>]<\/span><\/p>\n

# 1. reverse()：\u539f\u5730\u53cd\u8f6c，\u4fee\u6539\u539f\u5217\u8868，O(1)\u989d\u5916\u5185\u5b58<\/span>
\nnums.<\/span>reverse(<\/span>)<\/span>
\nprint<\/span>(<\/span>nums)<\/span> # [5, 4, 3, 2, 1]<\/span><\/p>\n

# 2. reversed()：\u8fd4\u56de\u8fed\u4ee3\u5668，\u4e0d\u521b\u5efa\u65b0\u5217\u8868<\/span>
\nnums =<\/span> [<\/span>1<\/span>,<\/span> 2<\/span>,<\/span> 3<\/span>,<\/span> 4<\/span>,<\/span> 5<\/span>]<\/span>
\nrev_iter =<\/span> reversed<\/span>(<\/span>nums)<\/span>
\nfor<\/span> x in<\/span> rev_iter:<\/span>
\n print<\/span>(<\/span>x,<\/span> end=<\/span>' '<\/span>)<\/span> # 5 4 3 2 1<\/span><\/p>\n

# 3. [::-1]：\u521b\u5efa\u65b0\u5217\u8868，O(n)\u5185\u5b58<\/span>
\nnums =<\/span> [<\/span>1<\/span>,<\/span> 2<\/span>,<\/span> 3<\/span>,<\/span> 4<\/span>,<\/span> 5<\/span>]<\/span>
\nnew_list =<\/span> nums[<\/span>:<\/span>:<\/span>–<\/span>1<\/span>]<\/span><\/p>\n

# \u9009\u62e9\u5efa\u8bae：<\/span>
\n# – \u9700\u8981\u4fee\u6539\u539f\u5217\u8868 \u2192 reverse()<\/span>
\n# – \u53ea\u9700\u8981\u53cd\u5411\u904d\u5386，\u4e0d\u5173\u5fc3\u987a\u5e8f \u2192 reversed()<\/span>
\n# – \u9700\u8981\u4fdd\u7559\u539f\u5217\u8868\u4e14\u9700\u8981\u65b0\u5217\u8868 \u2192 [::-1] \u6216 list(reversed(lst))<\/span><\/p>\n

\u516d\u3001\u5b9e\u6218：\u67e5\u627e\u6392\u5e8f\u7684\u7efc\u5408\u5e94\u7528<\/h3>\n

6.1 \u6392\u884c\u699c\u7cfb\u7edf<\/h4>\n

class<\/span> Leaderboard<\/span>:<\/span>
\n """\u6392\u884c\u699c\u2014\u2014\u7efc\u5408\u8fd0\u7528\u6392\u5e8f\u548c\u67e5\u627e"""<\/span><\/p>\n

def<\/span> __init__<\/span>(<\/span>self)<\/span>:<\/span>
\n self.<\/span>_entries =<\/span> [<\/span>]<\/span> # [(name, score), …]<\/span><\/p>\n

def<\/span> add_score<\/span>(<\/span>self,<\/span> name,<\/span> score)<\/span>:<\/span>
\n self.<\/span>_entries.<\/span>append(<\/span>(<\/span>name,<\/span> score)<\/span>)<\/span>
\n # \u6bcf\u6b21\u6dfb\u52a0\u540e\u6309\u5206\u6570\u964d\u5e8f\u6392\u5217<\/span>
\n self.<\/span>_entries.<\/span>sort(<\/span>key=<\/span>lambda<\/span> x:<\/span> x[<\/span>1<\/span>]<\/span>,<\/span> reverse=<\/span>True<\/span>)<\/span><\/p>\n

def<\/span> get_rank<\/span>(<\/span>self,<\/span> name)<\/span>:<\/span>
\n """\u83b7\u53d6\u67d0\u4eba\u7684\u6392\u540d（\u4ece1\u5f00\u59cb）"""<\/span>
\n for<\/span> i,<\/span> (<\/span>n,<\/span> s)<\/span> in<\/span> enumerate<\/span>(<\/span>self.<\/span>_entries)<\/span>:<\/span>
\n if<\/span> n ==<\/span> name:<\/span>
\n return<\/span> i +<\/span> 1<\/span>
\n return<\/span> –<\/span>1<\/span><\/p>\n

def<\/span> get_top_n<\/span>(<\/span>self,<\/span> n)<\/span>:<\/span>
\n """\u83b7\u53d6\u524dN\u540d"""<\/span>
\n return<\/span> self.<\/span>_entries[<\/span>:<\/span>n]<\/span><\/p>\n

def<\/span> get_around_player<\/span>(<\/span>self,<\/span> name,<\/span> radius=<\/span>2<\/span>)<\/span>:<\/span>
\n """\u83b7\u53d6\u67d0\u4eba\u524d\u540eradius\u540d\u7684\u73a9\u5bb6"""<\/span>
\n rank =<\/span> self.<\/span>get_rank(<\/span>name)<\/span>
\n if<\/span> rank ==<\/span> –<\/span>1<\/span>:<\/span>
\n return<\/span> [<\/span>]<\/span>
\n idx =<\/span> rank –<\/span> 1<\/span>
\n start =<\/span> max<\/span>(<\/span>0<\/span>,<\/span> idx –<\/span> radius)<\/span>
\n end =<\/span> min<\/span>(<\/span>len<\/span>(<\/span>self.<\/span>_entries)<\/span>,<\/span> idx +<\/span> radius +<\/span> 1<\/span>)<\/span>
\n return<\/span> self.<\/span>_entries[<\/span>start:<\/span>end]<\/span><\/p>\n

def<\/span> display<\/span>(<\/span>self)<\/span>:<\/span>
\n """\u663e\u793a\u6392\u884c\u699c"""<\/span>
\n for<\/span> i,<\/span> (<\/span>name,<\/span> score)<\/span> in<\/span> enumerate<\/span>(<\/span>self.<\/span>_entries,<\/span> 1<\/span>)<\/span>:<\/span>
\n print<\/span>(<\/span>f'<\/span>{<\/span>i:<\/span>2d<\/span>}<\/span><\/span>. <\/span>{<\/span>name:<\/span><6s<\/span>}<\/span><\/span> <\/span>{<\/span>score:<\/span>>5d<\/span>}<\/span><\/span>\u5206'<\/span><\/span>)<\/span><\/p>\n

lb =<\/span> Leaderboard(<\/span>)<\/span>
\nlb.<\/span>add_score(<\/span>'\u5c0f\u660e'<\/span>,<\/span> 850<\/span>)<\/span>
\nlb.<\/span>add_score(<\/span>'\u5c0f\u7ea2'<\/span>,<\/span> 920<\/span>)<\/span>
\nlb.<\/span>add_score(<\/span>'\u5c0f\u521a'<\/span>,<\/span> 780<\/span>)<\/span>
\nlb.<\/span>add_score(<\/span>'\u5c0f\u674e'<\/span>,<\/span> 950<\/span>)<\/span>
\nlb.<\/span>add_score(<\/span>'\u5c0f\u738b'<\/span>,<\/span> 880<\/span>)<\/span>
\nlb.<\/span>add_score(<\/span>'\u5c0f\u5f20'<\/span>,<\/span> 830<\/span>)<\/span><\/p>\n

print<\/span>(<\/span>'=== \u6392\u884c\u699c ==='<\/span>)<\/span>
\nlb.<\/span>display(<\/span>)<\/span><\/p>\n

print<\/span>(<\/span>f'\\\\n\u5c0f\u674e\u6392\u540d: \u7b2c<\/span>{<\/span>lb.<\/span>get_rank(<\/span>"\u5c0f\u674e"<\/span>)<\/span>}<\/span><\/span>\u540d'<\/span><\/span>)<\/span>
\nprint<\/span>(<\/span>f'\u524d3\u540d: <\/span>{<\/span>lb.<\/span>get_top_n(<\/span>3<\/span>)<\/span>}<\/span><\/span>'<\/span><\/span>)<\/span>
\nprint<\/span>(<\/span>f'\u5c0f\u521a\u5468\u56f4\u7684\u73a9\u5bb6: <\/span>{<\/span>lb.<\/span>get_around_player(<\/span>"\u5c0f\u521a"<\/span>,<\/span> 1<\/span>)<\/span>}<\/span><\/span>'<\/span><\/span>)<\/span><\/p>\n

6.2 \u4f18\u5148\u7ea7\u4efb\u52a1\u961f\u5217<\/h4>\n

class<\/span> PriorityTaskQueue<\/span>:<\/span>
\n """\u7528sort+key\u5b9e\u73b0\u7684\u4f18\u5148\u7ea7\u4efb\u52a1\u961f\u5217"""<\/span><\/p>\n

def<\/span> __init__<\/span>(<\/span>self)<\/span>:<\/span>
\n self.<\/span>_tasks =<\/span> [<\/span>]<\/span><\/p>\n

def<\/span> add_task<\/span>(<\/span>self,<\/span> name,<\/span> priority,<\/span> deadline)<\/span>:<\/span>
\n """\u6dfb\u52a0\u4efb\u52a1
\n priority: \u8d8a\u5c0f\u8d8a\u7d27\u6025（1=\u6700\u9ad8\u4f18\u5148\u7ea7）
\n deadline: \u622a\u6b62\u65f6\u95f4（\u65f6\u95f4\u6233）
\n """<\/span>
\n self.<\/span>_tasks.<\/span>append(<\/span>{<\/span>
\n 'name'<\/span>:<\/span> name,<\/span>
\n 'priority'<\/span>:<\/span> priority,<\/span>
\n 'deadline'<\/span>:<\/span> deadline,<\/span>
\n }<\/span>)<\/span><\/p>\n

def<\/span> get_next_task<\/span>(<\/span>self)<\/span>:<\/span>
\n """\u83b7\u53d6\u4e0b\u4e00\u4e2a\u8981\u6267\u884c\u7684\u4efb\u52a1"""<\/span>
\n if<\/span> not<\/span> self.<\/span>_tasks:<\/span>
\n return<\/span> None<\/span>
\n # \u6309\u4f18\u5148\u7ea7\u6392\u5e8f（priority\u5c0f\u7684\u4f18\u5148），\u540c\u4f18\u5148\u7ea7\u6309deadline\u6392\u5e8f<\/span>
\n self.<\/span>_tasks.<\/span>sort(<\/span>key=<\/span>lambda<\/span> t:<\/span> (<\/span>t[<\/span>'priority'<\/span>]<\/span>,<\/span> t[<\/span>'deadline'<\/span>]<\/span>)<\/span>)<\/span>
\n return<\/span> self.<\/span>_tasks.<\/span>pop(<\/span>0<\/span>)<\/span><\/p>\n

def<\/span> find_tasks_by_priority<\/span>(<\/span>self,<\/span> priority)<\/span>:<\/span>
\n """\u67e5\u627e\u6240\u6709\u6307\u5b9a\u4f18\u5148\u7ea7\u7684\u4efb\u52a1"""<\/span>
\n return<\/span> [<\/span>t for<\/span> t in<\/span> self.<\/span>_tasks if<\/span> t[<\/span>'priority'<\/span>]<\/span> ==<\/span> priority]<\/span><\/p>\n

def<\/span> pending_count<\/span>(<\/span>self)<\/span>:<\/span>
\n return<\/span> len<\/span>(<\/span>self.<\/span>_tasks)<\/span><\/p>\n

queue =<\/span> PriorityTaskQueue(<\/span>)<\/span>
\nqueue.<\/span>add_task(<\/span>'\u53d1\u9001\u90ae\u4ef6'<\/span>,<\/span> 2<\/span>,<\/span> 1000<\/span>)<\/span>
\nqueue.<\/span>add_task(<\/span>'\u6570\u636e\u5e93\u5907\u4efd'<\/span>,<\/span> 1<\/span>,<\/span> 900<\/span>)<\/span>
\nqueue.<\/span>add_task(<\/span>'\u751f\u6210\u62a5\u8868'<\/span>,<\/span> 2<\/span>,<\/span> 850<\/span>)<\/span>
\nqueue.<\/span>add_task(<\/span>'\u6e05\u7406\u65e5\u5fd7'<\/span>,<\/span> 3<\/span>,<\/span> 1200<\/span>)<\/span><\/p>\n

print<\/span>(<\/span>'\u6309\u4f18\u5148\u7ea7\u5904\u7406\u4efb\u52a1:'<\/span>)<\/span>
\nwhile<\/span> queue.<\/span>pending_count(<\/span>)<\/span> ><\/span> 0<\/span>:<\/span>
\n task =<\/span> queue.<\/span>get_next_task(<\/span>)<\/span>
\n print<\/span>(<\/span>f' \u5904\u7406: <\/span>{<\/span>task[<\/span>"name"<\/span>]<\/span>}<\/span><\/span> (\u4f18\u5148\u7ea7<\/span>{<\/span>task[<\/span>"priority"<\/span>]<\/span>}<\/span><\/span>)'<\/span><\/span>)<\/span><\/p>\n

6.3 \u4ef7\u683c\u6392\u5e8f\u4e0e\u8fc7\u6ee4\u7cfb\u7edf<\/h4>\n

def<\/span> sort_and_filter_products<\/span>(<\/span>products,<\/span> sort_by=<\/span>'price'<\/span>,<\/span> reverse=<\/span>False<\/span>,<\/span>
\n min_price=<\/span>None<\/span>,<\/span> max_price=<\/span>None<\/span>,<\/span>
\n keyword=<\/span>None<\/span>,<\/span> categories=<\/span>None<\/span>)<\/span>:<\/span>
\n """
\n \u7efc\u5408\u6392\u5e8f\u4e0e\u8fc7\u6ee4\u7684\u5546\u54c1\u5217\u8868\u5904\u7406
\n """<\/span>
\n result =<\/span> products[<\/span>:<\/span>]<\/span> # \u6d45\u62f7\u8d1d，\u4e0d\u5f71\u54cd\u539f\u6570\u636e<\/span><\/p>\n

# \u4ef7\u683c\u8fc7\u6ee4<\/span>
\n if<\/span> min_price is<\/span> not<\/span> None<\/span>:<\/span>
\n result =<\/span> [<\/span>p for<\/span> p in<\/span> result if<\/span> p[<\/span>'price'<\/span>]<\/span> >=<\/span> min_price]<\/span>
\n if<\/span> max_price is<\/span> not<\/span> None<\/span>:<\/span>
\n result =<\/span> [<\/span>p for<\/span> p in<\/span> result if<\/span> p[<\/span>'price'<\/span>]<\/span> <=<\/span> max_price]<\/span><\/p>\n

# \u5173\u952e\u8bcd\u641c\u7d22<\/span>
\n if<\/span> keyword:<\/span>
\n keyword =<\/span> keyword.<\/span>lower(<\/span>)<\/span>
\n result =<\/span> [<\/span>p for<\/span> p in<\/span> result
\n if<\/span> keyword in<\/span> p[<\/span>'name'<\/span>]<\/span>.<\/span>lower(<\/span>)<\/span>
\n or<\/span> keyword in<\/span> p.<\/span>get(<\/span>'description'<\/span>,<\/span> ''<\/span>)<\/span>.<\/span>lower(<\/span>)<\/span>]<\/span><\/p>\n

# \u5206\u7c7b\u8fc7\u6ee4<\/span>
\n if<\/span> categories:<\/span>
\n result =<\/span> [<\/span>p for<\/span> p in<\/span> result if<\/span> p[<\/span>'category'<\/span>]<\/span> in<\/span> categories]<\/span><\/p>\n

# \u6392\u5e8f<\/span>
\n sort_keys =<\/span> {<\/span>
\n 'price'<\/span>:<\/span> lambda<\/span> p:<\/span> p[<\/span>'price'<\/span>]<\/span>,<\/span>
\n 'sales'<\/span>:<\/span> lambda<\/span> p:<\/span> p.<\/span>get(<\/span>'sales'<\/span>,<\/span> 0<\/span>)<\/span>,<\/span>
\n 'rating'<\/span>:<\/span> lambda<\/span> p:<\/span> p.<\/span>get(<\/span>'rating'<\/span>,<\/span> 0<\/span>)<\/span>,<\/span>
\n 'name'<\/span>:<\/span> lambda<\/span> p:<\/span> p[<\/span>'name'<\/span>]<\/span>,<\/span>
\n }<\/span>
\n key_func =<\/span> sort_keys.<\/span>get(<\/span>sort_by,<\/span> lambda<\/span> p:<\/span> p[<\/span>'price'<\/span>]<\/span>)<\/span>
\n result.<\/span>sort(<\/span>key=<\/span>key_func,<\/span> reverse=<\/span>reverse)<\/span><\/p>\n

return<\/span> result<\/p>\n

products =<\/span> [<\/span>
\n {<\/span>'name'<\/span>:<\/span> 'Python\u7f16\u7a0b\u4e66'<\/span>,<\/span> 'price'<\/span>:<\/span> 59.9<\/span>,<\/span> 'sales'<\/span>:<\/span> 1500<\/span>,<\/span> 'rating'<\/span>:<\/span> 4.8<\/span>,<\/span> 'category'<\/span>:<\/span> '\u56fe\u4e66'<\/span>}<\/span>,<\/span>
\n {<\/span>'name'<\/span>:<\/span> '\u673a\u68b0\u952e\u76d8'<\/span>,<\/span> 'price'<\/span>:<\/span> 299<\/span>,<\/span> 'sales'<\/span>:<\/span> 800<\/span>,<\/span> 'rating'<\/span>:<\/span> 4.5<\/span>,<\/span> 'category'<\/span>:<\/span> '\u5916\u8bbe'<\/span>}<\/span>,<\/span>
\n {<\/span>'name'<\/span>:<\/span> '\u663e\u793a\u5668\u652f\u67b6'<\/span>,<\/span> 'price'<\/span>:<\/span> 159<\/span>,<\/span> 'sales'<\/span>:<\/span> 450<\/span>,<\/span> 'rating'<\/span>:<\/span> 4.3<\/span>,<\/span> 'category'<\/span>:<\/span> '\u5916\u8bbe'<\/span>}<\/span>,<\/span>
\n {<\/span>'name'<\/span>:<\/span> 'USB\u6570\u636e\u7ebf'<\/span>,<\/span> 'price'<\/span>:<\/span> 19.9<\/span>,<\/span> 'sales'<\/span>:<\/span> 3000<\/span>,<\/span> 'rating'<\/span>:<\/span> 4.6<\/span>,<\/span> 'category'<\/span>:<\/span> '\u914d\u4ef6'<\/span>}<\/span>,<\/span>
\n {<\/span>'name'<\/span>:<\/span> 'Python\u8fdb\u9636'<\/span>,<\/span> 'price'<\/span>:<\/span> 69.9<\/span>,<\/span> 'sales'<\/span>:<\/span> 1200<\/span>,<\/span> 'rating'<\/span>:<\/span> 4.9<\/span>,<\/span> 'category'<\/span>:<\/span> '\u56fe\u4e66'<\/span>}<\/span>,<\/span>
\n]<\/span><\/p>\n

# \u6309\u4ef7\u683c\u5347\u5e8f<\/span>
\nresult =<\/span> sort_and_filter_products(<\/span>products,<\/span> sort_by=<\/span>'price'<\/span>)<\/span>
\nprint<\/span>(<\/span>'\u6309\u4ef7\u683c\u5347\u5e8f:'<\/span>)<\/span>
\nfor<\/span> p in<\/span> result:<\/span>
\n print<\/span>(<\/span>f' <\/span>{<\/span>p[<\/span>"name"<\/span>]<\/span>}<\/span><\/span>: \u00a5<\/span>{<\/span>p[<\/span>"price"<\/span>]<\/span>}<\/span><\/span>'<\/span><\/span>)<\/span><\/p>\n

# \u6309\u8bc4\u5206\u964d\u5e8f<\/span>
\nresult =<\/span> sort_and_filter_products(<\/span>products,<\/span> sort_by=<\/span>'rating'<\/span>,<\/span> reverse=<\/span>True<\/span>)<\/span>
\nprint<\/span>(<\/span>'\\\\n\u6309\u8bc4\u5206\u964d\u5e8f:'<\/span>)<\/span>
\nfor<\/span> p in<\/span> result:<\/span>
\n print<\/span>(<\/span>f' <\/span>{<\/span>p[<\/span>"name"<\/span>]<\/span>}<\/span><\/span>: <\/span>{<\/span>p[<\/span>"rating"<\/span>]<\/span>}<\/span><\/span>\u5206'<\/span><\/span>)<\/span><\/p>\n

# \u4ef7\u683c\u572850-200\u4e4b\u95f4\u7684\u5916\u8bbe\u7c7b\u5546\u54c1<\/span>
\nresult =<\/span> sort_and_filter_products(<\/span>
\n products,<\/span> sort_by=<\/span>'sales'<\/span>,<\/span> reverse=<\/span>True<\/span>,<\/span>
\n min_price=<\/span>50<\/span>,<\/span> max_price=<\/span>200<\/span>,<\/span> categories=<\/span>[<\/span>'\u5916\u8bbe'<\/span>]<\/span>
\n)<\/span>
\nprint<\/span>(<\/span>'\\\\n\u5916\u8bbe\u7c7b(\u00a550-200)，\u6309\u9500\u91cf\u6392\u5e8f:'<\/span>)<\/span>
\nfor<\/span> p in<\/span> result:<\/span>
\n print<\/span>(<\/span>f' <\/span>{<\/span>p[<\/span>"name"<\/span>]<\/span>}<\/span><\/span>: \u00a5<\/span>{<\/span>p[<\/span>"price"<\/span>]<\/span>}<\/span><\/span>, \u9500\u91cf<\/span>{<\/span>p[<\/span>"sales"<\/span>]<\/span>}<\/span><\/span>'<\/span><\/span>)<\/span><\/p>\n

\u4e03\u3001Timsort\u2014\u2014Python\u6392\u5e8f\u7b97\u6cd5\u7b80\u4ecb<\/h3>\n

7.1 Timsort\u7684\u7279\u70b9<\/h4>\n

# Python\u7684sort\u4f7f\u7528Timsort（\u7531Tim Peters\u4e8e2002\u5e74\u8bbe\u8ba1）<\/span>
\n# \u5b83\u7ed3\u5408\u4e86\u5f52\u5e76\u6392\u5e8f\u548c\u63d2\u5165\u6392\u5e8f\u7684\u4f18\u70b9<\/span><\/p>\n

# \u6838\u5fc3\u7279\u70b9：<\/span>
\n# 1. \u7a33\u5b9a\u6392\u5e8f：\u76f8\u7b49\u5143\u7d20\u7684\u76f8\u5bf9\u987a\u5e8f\u4e0d\u53d8<\/span>
\n# 2. O(n log n) \u65f6\u95f4\u590d\u6742\u5ea6（\u6700\u574f\u60c5\u51b5）<\/span>
\n# 3. O(n) \u65f6\u95f4\u590d\u6742\u5ea6（\u6700\u597d\u60c5\u51b5\u2014\u2014\u5df2\u6392\u5e8f\u6570\u636e）<\/span>
\n# 4. \u5bf9\u90e8\u5206\u6709\u5e8f\u7684\u6570\u636e\u7279\u522b\u9ad8\u6548<\/span><\/p>\n

# \u6f14\u793a\u7a33\u5b9a\u6027<\/span>
\ndata =<\/span> [<\/span>
\n (<\/span>'\u5c0f\u660e'<\/span>,<\/span> 'A\u73ed'<\/span>,<\/span> 85<\/span>)<\/span>,<\/span>
\n (<\/span>'\u5c0f\u521a'<\/span>,<\/span> 'A\u73ed'<\/span>,<\/span> 78<\/span>)<\/span>,<\/span>
\n (<\/span>'\u5c0f\u7ea2'<\/span>,<\/span> 'B\u73ed'<\/span>,<\/span> 92<\/span>)<\/span>,<\/span>
\n]<\/span><\/p>\n

# \u5148\u6309\u6210\u7ee9\u6392\u5e8f<\/span>
\ndata.<\/span>sort(<\/span>key=<\/span>lambda<\/span> x:<\/span> x[<\/span>2<\/span>]<\/span>)<\/span>
\nprint<\/span>(<\/span>'\u6309\u6210\u7ee9\u6392\u5e8f\u540e:'<\/span>)<\/span>
\nfor<\/span> item in<\/span> data:<\/span>
\n print<\/span>(<\/span>f' <\/span>{<\/span>item}<\/span><\/span>'<\/span><\/span>)<\/span><\/p>\n

# \u518d\u6309\u73ed\u7ea7\u6392\u5e8f<\/span>
\ndata.<\/span>sort(<\/span>key=<\/span>lambda<\/span> x:<\/span> x[<\/span>1<\/span>]<\/span>)<\/span>
\nprint<\/span>(<\/span>'\u518d\u6309\u73ed\u7ea7\u6392\u5e8f\u540e（\u7a33\u5b9a\u6027\u4fdd\u8bc1\u540c\u73ed\u5185\u6210\u7ee9\u987a\u5e8f\u4e0d\u53d8）:'<\/span>)<\/span>
\nfor<\/span> item in<\/span> data:<\/span>
\n print<\/span>(<\/span>f' <\/span>{<\/span>item}<\/span><\/span>'<\/span><\/span>)<\/span>
\n# \u540c\u73ed\u7ea7\u7684\u5b66\u751f\u4f1a\u6309\u7167\u4e4b\u524d\u6392\u5e8f\u786e\u5b9a\u7684\u987a\u5e8f\u6392\u5217<\/span><\/p>\n

7.2 \u81ea\u5b9a\u4e49\u6bd4\u8f83\u5668（cmp_to_key）<\/h4>\n

# Python 3\u4e2d\u79fb\u9664\u4e86cmp\u53c2\u6570，\u7528functools.cmp_to_key\u66ff\u4ee3<\/span>
\nfrom<\/span> functools import<\/span> cmp_to_key<\/p>\n

# \u81ea\u5b9a\u4e49\u6bd4\u8f83\u51fd\u6570<\/span>
\ndef<\/span> compare_by_vowel_count<\/span>(<\/span>a,<\/span> b)<\/span>:<\/span>
\n """\u6309\u5143\u97f3\u5b57\u6bcd\u6570\u91cf\u6bd4\u8f83"""<\/span>
\n vowels =<\/span> set<\/span>(<\/span>'aeiouAEIOU'<\/span>)<\/span>
\n count_a =<\/span> sum<\/span>(<\/span>1<\/span> for<\/span> c in<\/span> a if<\/span> c in<\/span> vowels)<\/span>
\n count_b =<\/span> sum<\/span>(<\/span>1<\/span> for<\/span> c in<\/span> b if<\/span> c in<\/span> vowels)<\/span>
\n return<\/span> count_a –<\/span> count_b # \u8fd4\u56de\u8d1f\u6570\u8868\u793aa<b，\u6b63\u6570a>b，0\u8868\u793a\u76f8\u7b49<\/span><\/p>\n

words =<\/span> [<\/span>'hello'<\/span>,<\/span> 'world'<\/span>,<\/span> 'python'<\/span>,<\/span> 'programming'<\/span>,<\/span> 'beautiful'<\/span>,<\/span> 'sky'<\/span>]<\/span>
\nwords.<\/span>sort(<\/span>key=<\/span>cmp_to_key(<\/span>compare_by_vowel_count)<\/span>)<\/span>
\nprint<\/span>(<\/span>words)<\/span> # ['sky', 'world', 'python', 'hello', 'beautiful', 'programming']<\/span>
\n# sky(1\u4e2a\u5143\u97f3?) world(1), python(1), hello(2), beautiful(5), programming(3)<\/span>
\n# \u5b9e\u9645\u6309\u5143\u97f3\u6570\u5347\u5e8f\u6392\u5217<\/span><\/p>\n

# \u867d\u7136cmp_to_key\u80fd\u7528，\u4f46\u901a\u5e38\u7528key+lambda\u66f4\u9ad8\u6548<\/span>
\n# \u4e0a\u9762\u7684\u4f8b\u5b50\u53ef\u4ee5\u6539\u5199\u4e3a：<\/span>
\nwords.<\/span>sort(<\/span>key=<\/span>lambda<\/span> w:<\/span> sum<\/span>(<\/span>1<\/span> for<\/span> c in<\/span> w if<\/span> c in<\/span> 'aeiouAEIOU'<\/span>)<\/span>)<\/span><\/p>\n

\u516b\u3001\u6027\u80fd\u4e0e\u6700\u4f73\u5b9e\u8df5<\/h3>\n

# 1. \u6392\u5e8f\u4e86\u5927\u91cf\u6570\u636e\u65f6，sort()\u6bd4sorted()\u7701\u5185\u5b58<\/span>
\nimport<\/span> time<\/p>\n

n =<\/span> 1000000<\/span>
\ndata =<\/span> list<\/span>(<\/span>range<\/span>(<\/span>n,<\/span> 0<\/span>,<\/span> –<\/span>1<\/span>)<\/span>)<\/span> # \u964d\u5e8f\u5217\u8868<\/span><\/p>\n

start =<\/span> time.<\/span>perf_counter(<\/span>)<\/span>
\ndata.<\/span>sort(<\/span>)<\/span>
\nt1 =<\/span> time.<\/span>perf_counter(<\/span>)<\/span> –<\/span> start
\nprint<\/span>(<\/span>f'sort()\u539f\u5730\u6392\u5e8f: <\/span>{<\/span>t1:<\/span>.3f<\/span>}<\/span><\/span>\u79d2'<\/span><\/span>)<\/span><\/p>\n

data =<\/span> list<\/span>(<\/span>range<\/span>(<\/span>n,<\/span> 0<\/span>,<\/span> –<\/span>1<\/span>)<\/span>)<\/span>
\nstart =<\/span> time.<\/span>perf_counter(<\/span>)<\/span>
\nsorted_data =<\/span> sorted<\/span>(<\/span>data)<\/span>
\nt2 =<\/span> time.<\/span>perf_counter(<\/span>)<\/span> –<\/span> start
\nprint<\/span>(<\/span>f'sorted()\u521b\u5efa\u65b0\u5217\u8868: <\/span>{<\/span>t2:<\/span>.3f<\/span>}<\/span><\/span>\u79d2'<\/span><\/span>)<\/span><\/p>\n

# 2. \u9891\u7e41\u67e5\u627e\u65f6，\u8003\u8651\u8f6c\u4e3aset<\/span>
\n# \u5bf9\u4e8e"\u662f\u5426\u5b58\u5728"\u7684\u67e5\u8be2，set\u662fO(1)，list\u7684in\u662fO(n)<\/span>
\ndata_list =<\/span> list<\/span>(<\/span>range<\/span>(<\/span>10000<\/span>)<\/span>)<\/span>
\ndata_set =<\/span> set<\/span>(<\/span>data_list)<\/span><\/p>\n

start =<\/span> time.<\/span>perf_counter(<\/span>)<\/span>
\nfor<\/span> _ in<\/span> range<\/span>(<\/span>10000<\/span>)<\/span>:<\/span>
\n _ =<\/span> 9999<\/span> in<\/span> data_list
\nt_list =<\/span> time.<\/span>perf_counter(<\/span>)<\/span> –<\/span> start
\nprint<\/span>(<\/span>f'list in\u67e5\u8be2: <\/span>{<\/span>t_list:<\/span>.4f<\/span>}<\/span><\/span>\u79d2'<\/span><\/span>)<\/span><\/p>\n

start =<\/span> time.<\/span>perf_counter(<\/span>)<\/span>
\nfor<\/span> _ in<\/span> range<\/span>(<\/span>10000<\/span>)<\/span>:<\/span>
\n _ =<\/span> 9999<\/span> in<\/span> data_set
\nt_set =<\/span> time.<\/span>perf_counter(<\/span>)<\/span> –<\/span> start
\nprint<\/span>(<\/span>f'set in\u67e5\u8be2: <\/span>{<\/span>t_set:<\/span>.4f<\/span>}<\/span><\/span>\u79d2'<\/span><\/span>)<\/span>
\nprint<\/span>(<\/span>f'set\u5feb <\/span>{<\/span>t_list \/<\/span> t_set:<\/span>.0f<\/span>}<\/span><\/span> \u500d'<\/span><\/span>)<\/span><\/p>\n

# 3. key\u51fd\u6570\u4f1a\u88ab\u8c03\u7528N\u6b21，\u5e94\u5c3d\u91cf\u7b80\u5355<\/span>
\n# \u4e0d\u63a8\u8350：\u5728key\u4e2d\u505a\u590d\u6742\u8ba1\u7b97<\/span>
\n# \u63a8\u8350：\u9884\u5148\u8ba1\u7b97\u597d\u6392\u5e8f\u952e<\/span>
\ndata =<\/span> [<\/span>'hello'<\/span>,<\/span> 'world'<\/span>,<\/span> 'python'<\/span>,<\/span> 'programming'<\/span>]<\/span>
\n# \u5982\u679c\u6392\u5e8f\u952e\u8ba1\u7b97\u5f88\u6602\u8d35<\/span>
\nword_lengths =<\/span> {<\/span>w:<\/span> len<\/span>(<\/span>w)<\/span> for<\/span> w in<\/span> data}<\/span>
\ndata.<\/span>sort(<\/span>key=<\/span>word_lengths.<\/span>get)<\/span> # \u5b57\u5178\u67e5\u627e\u662fO(1)<\/span><\/p>\n

# 4. \u90e8\u5206\u6392\u5e8f\u7528heapq<\/span>
\nimport<\/span> heapq
\nscores =<\/span> [<\/span>85<\/span>,<\/span> 92<\/span>,<\/span> 78<\/span>,<\/span> 95<\/span>,<\/span> 88<\/span>,<\/span> 76<\/span>,<\/span> 91<\/span>,<\/span> 89<\/span>,<\/span> 94<\/span>,<\/span> 83<\/span>]<\/span>
\n# \u53ea\u9700\u8981\u524d3\u540d<\/span>
\ntop3 =<\/span> heapq.<\/span>nlargest(<\/span>3<\/span>,<\/span> scores)<\/span>
\nprint<\/span>(<\/span>f'\u524d3\u540d: <\/span>{<\/span>top3}<\/span><\/span>'<\/span><\/span>)<\/span> # [95, 94, 92]<\/span><\/p>\n

bottom3 =<\/span> heapq.<\/span>nsmallest(<\/span>3<\/span>,<\/span> scores)<\/span>
\nprint<\/span>(<\/span>f'\u540e3\u540d: <\/span>{<\/span>bottom3}<\/span><\/span>'<\/span><\/span>)<\/span> # [76, 78, 83]<\/span><\/p>\n

\u4e5d\u3001\u672c\u7bc7\u5c0f\u7ed3<\/h3>\n

\u2705 \u5217\u8868\u67e5\u627e\u3001\u6392\u5e8f\u3001\u53cd\u8f6c\u6838\u5fc3\u65b9\u6cd5\u901f\u67e5：<\/p>\n

\u67e5\u627e：<\/p>\n