{"id":655,"date":"2026-03-10T13:25:00","date_gmt":"2026-03-10T05:25:00","guid":{"rendered":"https:\/\/mitongxue.cn\/?p=655"},"modified":"2026-07-14T13:52:15","modified_gmt":"2026-07-14T05:52:15","slug":"python-lambda%e8%a1%a8%e8%be%be%e5%bc%8f","status":"publish","type":"post","link":"https:\/\/mitongxue.cn\/index.php\/2026\/03\/10\/python-lambda%e8%a1%a8%e8%be%be%e5%bc%8f\/","title":{"rendered":"python Lambda\u8868\u8fbe\u5f0f"},"content":{"rendered":"\n

Lambda\u8868\u8fbe\u5f0f\u7528\u4e8e\u521b\u5efa\u533f\u540d\u51fd\u6570<\/strong>\u2014\u2014\u5373\u6ca1\u6709\u540d\u79f0\u7684\u4e34\u65f6\u51fd\u6570\u3002\u5f53\u4f60\u9700\u8981\u4e00\u4e2a\u7b80\u5355\u51fd\u6570\u4e14\u53ea\u7528\u4e00\u6b21\u65f6\uff0clambda\u80fd\u8ba9\u4ee3\u7801\u66f4\u7b80\u6d01\u3002<\/p>\n\n\n\n

\u57fa\u672c\u8bed\u6cd5<\/h2>\n\n\n\n
lambda \u53c2\u65701, \u53c2\u65702, ... : \u8868\u8fbe\u5f0f<\/pre>\n\n\n\n
# \u666e\u901a\u51fd\u6570
def add(x, y):
    return x + y
\u200b
# \u7b49\u4ef7\u7684lambda
add_lambda = lambda x, y: x + y
\u200b
print(add(2, 3))         # 5
print(add_lambda(2, 3))  # 5<\/code><\/pre>\n\n\n\n
\u7279\u70b9\uff1a<\/strong><\/p>\n\n\n\n
    \n
  • \u53ea\u80fd\u5305\u542b\u4e00\u4e2a\u8868\u8fbe\u5f0f<\/strong>\uff0c\u4e0d\u80fd\u5199\u591a\u6761\u8bed\u53e5<\/li>\n\n\n\n
  • \u8868\u8fbe\u5f0f\u7684\u8ba1\u7b97\u7ed3\u679c\u81ea\u52a8\u8fd4\u56de<\/strong><\/li>\n\n\n\n
  • \u901a\u5e38\u4e0d\u547d\u540d\uff0c\u5373\u7528\u5373\u8d70<\/li>\n<\/ul>\n\n\n\n
    \u5185\u7f6e\u9ad8\u9636\u51fd\u6570<\/h2>\n\n\n\n
    \u9ad8\u9636\u51fd\u6570\u662f\u6307\u63a5\u6536\u51fd\u6570\u4f5c\u4e3a\u53c2\u6570\u7684\u51fd\u6570\u3002\u8fd9\u662flambda\u6700\u7ecf\u5178\u7684\u4f7f\u7528\u573a\u666f\u3002<\/p>\n\n\n\n
    map()<\/code> \u2014 \u6620\u5c04<\/h3>\n\n\n\n
    \u5bf9\u53ef\u8fed\u4ee3\u5bf9\u8c61\u7684\u6bcf\u4e2a\u5143\u7d20\u6267\u884c\u6307\u5b9a\u64cd\u4f5c\uff0c\u8fd4\u56de\u7ed3\u679c\u7684\u8fed\u4ee3\u5668\u3002<\/p>\n\n\n\n
    1. map()<\/code> \u7684\u8fd4\u56de\u503c\u4e0d\u662f\u5217\u8868\uff0c\u662f\u8fed\u4ee3\u5668\u5bf9\u8c61\uff08map \u8fed\u4ee3\u5668\uff09<\/strong><\/h5>\n\n\n\n
    Python3 \u4e2d map(function, iterable)<\/code> \u4e0d\u4f1a\u76f4\u63a5\u751f\u6210\u5b8c\u6574\u5217\u8868\uff0c\u800c\u662f\u8fd4\u56de\u60f0\u6027\u8fed\u4ee3\u5668 map object<\/code>\uff1a<\/p>\n\n\n\n
      \n
    • \u60f0\u6027\uff1a\u4e0d\u4e00\u6b21\u6027\u8ba1\u7b97\u6240\u6709\u7ed3\u679c<\/strong>\uff0c\u53ea\u6709\u904d\u5386\u7684\u65f6\u5019\u624d\u9010\u4e2a\u8ba1\u7b97\uff1b<\/li>\n\n\n\n
    • \u4f18\u70b9\uff1a\u8282\u7701\u5185\u5b58\uff0c\u5904\u7406\u8d85\u5927\u5e8f\u5217\u4e0d\u4f1a\u4e00\u6b21\u6027\u5360\u7528\u5927\u91cf\u7a7a\u95f4\uff1b<\/li>\n\n\n\n
    • \u7f3a\u70b9\uff1a\u76f4\u63a5\u6253\u5370\u53ea\u4f1a\u8f93\u51fa\u5bf9\u8c61\u5185\u5b58\u5730\u5740\uff0c\u770b\u4e0d\u5230\u6570\u636e\uff0c\u4e5f\u4e0d\u80fd\u7528\u4e0b\u6807\u3001len ()\u3002<\/li>\n\n\n\n
    • list(\u8fed\u4ee3\u5668)<\/code> \u4f1a\u4ece\u5934\u5230\u5c3e\u904d\u5386\u8fed\u4ee3\u5668<\/strong>\uff0c\u628a\u6240\u6709\u8ba1\u7b97\u7ed3\u679c\u53d6\u51fa\u5b58\u5165\u65b0\u5217\u8868\uff1a<\/li>\n<\/ul>\n\n\n\n
      numbers = [1, 2, 3, 4, 5]\n\n# \u666e\u901a\u5199\u6cd5\ndef square(x):\n    return x ** 2\n\nresult = map(square, numbers)\nprint(list(result))  # [1, 4, 9, 16, 25]\n\n# lambda\u5199\u6cd5\u2014\u2014\u66f4\u7b80\u6d01\nresult = map(lambda x: x ** 2, numbers)\nprint(list(result))  # [1, 4, 9, 16, 25]<\/code><\/pre>\n\n\n\n
      <\/p>\n\n\n\n
      map()<\/code> \u76f8\u5f53\u4e8e\uff1a<\/strong> \u5bf9\u5217\u8868\u6bcf\u4e2a\u5143\u7d20\u505a”\u8f6c\u6362”\u3002<\/p>\n\n\n\n
      # \u5c06\u5b57\u7b26\u4e32\u5217\u8868\u8f6c\u4e3a\u957f\u5ea6\u5217\u8868
      names = [\"Alice\", \"Bob\", \"Charlie\"]
      lengths = map(lambda s: len(s), names)
      print(list(lengths))  # [5, 3, 7]
      \u200b
      # \u4e24\u4e2a\u5217\u8868\u5bf9\u5e94\u5143\u7d20\u76f8\u52a0
      a = [1, 2, 3]
      b = [10, 20, 30]
      sums = map(lambda x, y: x + y, a, b)
      print(list(sums))  # [11, 22, 33]<\/code><\/pre>\n\n\n\n
      \n\n\n\n
      \u8fed\u4ee3\u5668\u7684\u7279\u6027\uff1a\u53ea\u80fd\u904d\u5386\u4e00\u6b21<\/h4>\n\n\n\n
      map \u8fed\u4ee3\u5668\u6d88\u8017\u5b8c\u5c31\u7a7a\u4e86\uff0c\u518d\u6b21\u904d\u5386\u65e0\u6570\u636e\uff1a<\/p>\n\n\n\n
      \u9664\u4e86 list\uff0c\u5176\u4ed6\u80fd\u6d88\u8d39\u8fed\u4ee3\u5668\u7684\u65b9\u5f0f<\/h5>\n\n\n\n
      \u4e0d\u60f3\u7528 list\uff0c\u4e5f\u53ef\u4ee5\u5faa\u73af\u904d\u5386\u53d6\u503c\uff1a<\/p>\n\n\n\n
      nums = [1,2,3]
      m = map(lambda x:x**2, nums)
      for val in m:
          print(val)<\/code><\/pre>\n\n\n\n
      \u5bf9\u6bd4 Python2 \u5c0f\u8865\u5145<\/h4>\n\n\n\n
      Python2 \u7684<\/p>\n\n\n\n
      map<\/code><\/pre>\n\n\n\n
      \u76f4\u63a5\u8fd4\u56de\u5217\u8868\uff0c\u4e0d\u9700\u8981\u5957 list\uff1b<\/p>\n\n\n\n
      Python3 \u6539\u6210\u8fed\u4ee3\u5668\uff0c\u662f\u4e3a\u4e86\u5185\u5b58\u4f18\u5316\uff0c\u6240\u4ee5\u5fc5\u987b\u624b\u52a8\u8f6c\u5217\u8868\u3002<\/p>\n\n\n\n
      nums = [1,2,3]
      m = map(lambda x:x**2, nums)
      print(list(m)) # [1,4,9]
      print(list(m)) # [] \u8fed\u4ee3\u5668\u5df2\u7ecf\u8017\u5c3d<\/code><\/pre>\n\n\n\n
      \u8f6c\u6210 list \u540e\u6570\u636e\u6c38\u4e45\u4fdd\u5b58\uff0c\u53ef\u4ee5\u53cd\u590d\u8bfb\u53d6\u3001\u5207\u7247\u3001\u53d6\u957f\u5ea6\u3002<\/p>\n\n\n\n
      filter()<\/code> \u2014 \u8fc7\u6ee4<\/h3>\n\n\n\n
      \u6839\u636e\u6761\u4ef6\u7b5b\u9009\u53ef\u8fed\u4ee3\u5bf9\u8c61\u4e2d\u7684\u5143\u7d20\uff0c\u4fdd\u7559\u6ee1\u8db3\u6761\u4ef6\u7684\u3002<\/p>\n\n\n\n
      numbers = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]
      \u200b
      # \u7b5b\u9009\u5076\u6570
      evens = filter(lambda x: x % 2 == 0, numbers)
      print(list(evens))  # [2, 4, 6, 8, 10]
      \u200b
      # \u7b5b\u9009\u957f\u5ea6\u5927\u4e8e3\u7684\u5b57\u7b26\u4e32
      words = [\"cat\", \"elephant\", \"dog\", \"butterfly\"]
      long_words = filter(lambda s: len(s) > 3, words)
      print(list(long_words))  # ['elephant', 'butterfly']<\/code><\/pre>\n\n\n\n
      filter()<\/code> \u76f8\u5f53\u4e8e\uff1a<\/strong> \u6309\u6761\u4ef6”\u7b5b\u9009”\u5217\u8868\u3002<\/p>\n\n\n\n
      # \u7b5b\u9009\u6b63\u6570
      nums = [-2, -1, 0, 1, 2]
      positives = filter(lambda x: x > 0, nums)
      print(list(positives))  # [1, 2]<\/code><\/pre>\n\n\n\n
      \n\n\n\n
      sorted()<\/code> \u2014 \u6392\u5e8f\uff08\u6307\u5b9akey\uff09<\/h3>\n\n\n\n
      sorted()<\/code> \u548c\u5217\u8868\u7684 .sort()<\/code> \u90fd\u652f\u6301 key<\/code> \u53c2\u6570\uff0c\u7528\u4e8e\u6307\u5b9a”\u6309\u4ec0\u4e48\u6392\u5e8f”\u3002<\/p>\n\n\n\n
      words = [\"banana\", \"pie\", \"Washington\", \"book\"]
      \u200b
      # \u6309\u957f\u5ea6\u6392\u5e8f
      sorted_by_len = sorted(words, key=lambda s: len(s))
      print(sorted_by_len)  # ['pie', 'book', 'banana', 'Washington']
      \u200b
      # \u6309\u6700\u540e\u4e00\u4e2a\u5b57\u6bcd\u6392\u5e8f
      sorted_by_last = sorted(words, key=lambda s: s[-1])
      print(sorted_by_last)  # ['banana', 'pie', 'book', 'Washington']
      \u200b
      # \u964d\u5e8f\u6392\u5e8f
      sorted_desc = sorted(words, key=lambda s: len(s), reverse=True)
      print(sorted_desc)  # ['Washington', 'banana', 'book', 'pie']<\/code><\/pre>\n\n\n\n
      # \u6309\u7edd\u5bf9\u503c\u6392\u5e8f
      nums = [-5, 2, -8, 1, -9]
      sorted_by_abs = sorted(nums, key=lambda x: abs(x))
      print(sorted_by_abs)  # [1, 2, -5, -8, -9]<\/code><\/pre>\n\n\n\n
      \n\n\n\n
      max()<\/code> \/ min()<\/code> \u2014 \u6781\u503c\uff08\u6307\u5b9akey\uff09<\/h3>\n\n\n\n
      words = [\"apple\", \"banana\", \"cherry\"]
      \u200b
      # \u627e\u51fa\u6700\u957f\u7684\u5355\u8bcd
      longest = max(words, key=lambda s: len(s))
      print(longest)  # banana
      \u200b
      # \u627e\u51fa\u6700\u77ed\u7684\u5355\u8bcd
      shortest = min(words, key=lambda s: len(s))
      print(shortest)  # apple<\/code><\/pre>\n\n\n\n
      students = [
          {\"name\": \"Alice\", \"score\": 85},
          {\"name\": \"Bob\", \"score\": 92},
          {\"name\": \"Charlie\", \"score\": 78}
      ]
      \u200b
      # \u627e\u51fa\u5206\u6570\u6700\u9ad8\u7684\u5b66\u751f
      top_student = max(students, key=lambda s: s[\"score\"])
      print(top_student)  # {'name': 'Bob', 'score': 92}<\/code><\/pre>\n\n\n\n
      \n\n\n\n
      reduce()<\/code> \u2014 \u7d2f\u79ef\u8ba1\u7b97<\/h3>\n\n\n\n
      reduce()<\/code> \u5728 functools<\/code> \u6a21\u5757\u4e2d\uff0c\u7528\u4e8e\u5c06\u5e8f\u5217\u9010\u4e2a\u7d2f\u79ef\u8ba1\u7b97\u4e3a\u4e00\u4e2a\u503c\u3002<\/p>\n\n\n\n
      from functools import reduce
      \u200b
      numbers = [1, 2, 3, 4, 5]
      \u200b
      # \u6c42\u548c
      total = reduce(lambda x, y: x + y, numbers)
      print(total)  # 15
      \u200b
      # \u6c42\u79ef
      product = reduce(lambda x, y: x * y, numbers)
      print(product)  # 120
      \u200b
      # \u6c42\u6700\u5927\u503c
      maximum = reduce(lambda x, y: x if x > y else y, numbers)
      print(maximum)  # 5<\/code><\/pre>\n\n\n\n
      \n\n\n\n
      <\/p>\n","protected":false},"excerpt":{"rendered":"
      Lambda\u8868\u8fbe\u5f0f\u7528\u4e8e\u521b\u5efa\u533f\u540d\u51fd\u6570\u2014\u2014\u5373\u6ca1\u6709\u540d\u79f0\u7684..<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[52,14],"tags":[],"class_list":["post-655","post","type-post","status-publish","format-standard","hentry","category-python","category-back"],"featured_image_urls":{"full":"","thumbnail":"","medium":"","medium_large":"","large":"","1536x1536":"","2048x2048":""},"author_info":{"info":["\u9648 \u67d0\u4eba"]},"category_info":"Python<\/a> \u540e\u7aef<\/a>","tag_info":"\u540e\u7aef","comment_count":"0","_links":{"self":[{"href":"https:\/\/mitongxue.cn\/index.php\/wp-json\/wp\/v2\/posts\/655","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/mitongxue.cn\/index.php\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/mitongxue.cn\/index.php\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/mitongxue.cn\/index.php\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/mitongxue.cn\/index.php\/wp-json\/wp\/v2\/comments?post=655"}],"version-history":[{"count":1,"href":"https:\/\/mitongxue.cn\/index.php\/wp-json\/wp\/v2\/posts\/655\/revisions"}],"predecessor-version":[{"id":656,"href":"https:\/\/mitongxue.cn\/index.php\/wp-json\/wp\/v2\/posts\/655\/revisions\/656"}],"wp:attachment":[{"href":"https:\/\/mitongxue.cn\/index.php\/wp-json\/wp\/v2\/media?parent=655"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/mitongxue.cn\/index.php\/wp-json\/wp\/v2\/categories?post=655"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/mitongxue.cn\/index.php\/wp-json\/wp\/v2\/tags?post=655"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}