{"id":950107,"date":"2024-12-27T00:25:32","date_gmt":"2024-12-26T16:25:32","guid":{"rendered":"https:\/\/docs.pingcode.com\/ask\/ask-ask\/950107.html"},"modified":"2024-12-27T00:25:34","modified_gmt":"2024-12-26T16:25:34","slug":"python%e4%b8%ad%e5%a6%82%e4%bd%95find","status":"publish","type":"post","link":"https:\/\/docs.pingcode.com\/ask\/ask-ask\/950107.html","title":{"rendered":"python\u4e2d\u5982\u4f55find"},"content":{"rendered":"

\"python\u4e2d\u5982\u4f55find\"<\/p>\n

\u5728Python\u4e2d\uff0cfind<\/code>\u65b9\u6cd5\u4e3b\u8981\u7528\u4e8e\u5b57\u7b26\u4e32\u64cd\u4f5c\u3002\u53ef\u4ee5\u4f7f\u7528\u5b57\u7b26\u4e32\u7684find()<\/code>\u65b9\u6cd5\u67e5\u627e\u5b50\u5b57\u7b26\u4e32\u5728\u5b57\u7b26\u4e32\u4e2d\u7684\u4f4d\u7f6e\u3001\u5982\u679c\u5b50\u5b57\u7b26\u4e32\u4e0d\u5b58\u5728\uff0c\u5219\u8fd4\u56de-1\u3001\u9664\u6b64\u4e4b\u5916\uff0c\u8fd8\u53ef\u4ee5\u4f7f\u7528index()<\/code>\u65b9\u6cd5\uff0c\u5b83\u4e0efind()<\/code>\u7c7b\u4f3c\uff0c\u4f46\u5728\u5b50\u5b57\u7b26\u4e32\u4e0d\u5b58\u5728\u65f6\u4f1a\u5f15\u53d1\u5f02\u5e38<\/strong>\u3002\u63a5\u4e0b\u6765\uff0c\u6211\u4eec\u5c06\u8be6\u7ec6\u8ba8\u8bbaPython\u4e2d\u5b57\u7b26\u4e32\u67e5\u627e\u7684\u5404\u79cd\u65b9\u6cd5\u548c\u6280\u5de7\u3002<\/p>\n<\/p>\n

\u4e00\u3001STRING FIND()\u65b9\u6cd5<\/h2>\n<\/p>\n

find()<\/code>\u65b9\u6cd5\u7528\u4e8e\u67e5\u627e\u5b50\u5b57\u7b26\u4e32\u5728\u5b57\u7b26\u4e32\u4e2d\u7684\u6700\u5de6\u4fa7\u4f4d\u7f6e\u3002\u5b83\u8fd4\u56de\u5b50\u5b57\u7b26\u4e32\u7684\u8d77\u59cb\u7d22\u5f15\uff0c\u5982\u679c\u5b50\u5b57\u7b26\u4e32\u4e0d\u5b58\u5728\uff0c\u5219\u8fd4\u56de-1\u3002<\/p>\n<\/p>\n

\u7528\u6cd5<\/h3>\n<\/p>\n

str.find(sub[, start[, end]])<\/p>\n
<\/code><\/pre>\n<\/p>\n
\u53c2\u6570\u8bf4\u660e<\/h3>\n<\/p>\n
    \n
  • sub<\/strong>: \u8981\u67e5\u627e\u7684\u5b50\u5b57\u7b26\u4e32\u3002<\/li>\n
  • start<\/strong>: \u53ef\u9009\u53c2\u6570\uff0c\u6307\u5b9a\u641c\u7d22\u7684\u8d77\u59cb\u4f4d\u7f6e\u3002<\/li>\n
  • end<\/strong>: \u53ef\u9009\u53c2\u6570\uff0c\u6307\u5b9a\u641c\u7d22\u7684\u7ed3\u675f\u4f4d\u7f6e\u3002<\/li>\n<\/ul>\n
    \u793a\u4f8b<\/h3>\n<\/p>\n
    text = "Hello, welcome to the world of Python."<\/p>\n
    position = text.find("welcome")<\/p>\n
    print(position)  # \u8f93\u51fa: 7<\/p>\n
    \u5e26\u8d77\u59cb\u548c\u7ed3\u675f\u4f4d\u7f6e<\/strong><\/h2>\n
    position = text.find("o", 10, 20)<\/p>\n
    print(position)  # \u8f93\u51fa: 16<\/p>\n
    <\/code><\/pre>\n<\/p>\n
    \u4e8c\u3001STRING INDEX()\u65b9\u6cd5<\/h2>\n<\/p>\n
    index()<\/code>\u65b9\u6cd5\u4e0efind()<\/code>\u65b9\u6cd5\u7c7b\u4f3c\uff0c\u4f46\u5982\u679c\u5b50\u5b57\u7b26\u4e32\u4e0d\u5b58\u5728\uff0c\u5219\u4f1a\u5f15\u53d1ValueError<\/code>\u5f02\u5e38\uff0c\u800c\u4e0d\u662f\u8fd4\u56de-1\u3002<\/p>\n<\/p>\n
    \u7528\u6cd5<\/h3>\n<\/p>\n
    str.index(sub[, start[, end]])<\/p>\n
    <\/code><\/pre>\n<\/p>\n
    \u793a\u4f8b<\/h3>\n<\/p>\n
    try:<\/p>\n
        position = text.index("Python")<\/p>\n
        print(position)  # \u8f93\u51fa: 31<\/p>\n
    except ValueError:<\/p>\n
        print("\u5b50\u5b57\u7b26\u4e32\u672a\u627e\u5230")<\/p>\n
    <\/code><\/pre>\n<\/p>\n
    \u4e09\u3001USING IN OPERATOR<\/h2>\n<\/p>\n
    \u9664\u4e86find()<\/code>\u548cindex()<\/code>\u65b9\u6cd5\uff0cPython\u8fd8\u63d0\u4f9b\u4e86in<\/code>\u8fd0\u7b97\u7b26\u6765\u68c0\u67e5\u5b57\u7b26\u4e32\u4e2d\u662f\u5426\u5b58\u5728\u5b50\u5b57\u7b26\u4e32\u3002\u867d\u7136in<\/code>\u8fd0\u7b97\u7b26\u65e0\u6cd5\u76f4\u63a5\u8fd4\u56de\u4f4d\u7f6e\uff0c\u4f46\u5b83\u662f\u68c0\u67e5\u5b58\u5728\u6027\u7684\u7b80\u6d01\u65b9\u6cd5<\/strong>\u3002<\/p>\n<\/p>\n
    \u793a\u4f8b<\/h3>\n<\/p>\n
    if "world" in text:<\/p>\n
        print("\u5b50\u5b57\u7b26\u4e32\u5b58\u5728")<\/p>\n
    else:<\/p>\n
        print("\u5b50\u5b57\u7b26\u4e32\u4e0d\u5b58\u5728")<\/p>\n
    <\/code><\/pre>\n<\/p>\n
    \u56db\u3001USING REGULAR EXPRESSIONS<\/h2>\n<\/p>\n
    \u5bf9\u4e8e\u66f4\u590d\u6742\u7684\u5b57\u7b26\u4e32\u67e5\u627e\uff0c\u6b63\u5219\u8868\u8fbe\u5f0f\u662f\u4e00\u4e2a\u5f3a\u5927\u7684\u5de5\u5177\u3002Python\u7684re<\/code>\u6a21\u5757\u63d0\u4f9b\u4e86\u6b63\u5219\u8868\u8fbe\u5f0f\u7684\u652f\u6301\u3002<\/p>\n<\/p>\n
    \u7528\u6cd5<\/h3>\n<\/p>\n
    import re<\/p>\n
    \u4f7f\u7528re.search()\u67e5\u627e<\/strong><\/h2>\n
    match = re.search(r"world", text)<\/p>\n
    if match:<\/p>\n
        print("Found:", match.start())<\/p>\n
    else:<\/p>\n
        print("Not found")<\/p>\n
    <\/code><\/pre>\n<\/p>\n
    \u4e94\u3001STRING RINDEX()\u65b9\u6cd5<\/h2>\n<\/p>\n
    rindex()<\/code>\u65b9\u6cd5\u4e0eindex()<\/code>\u7c7b\u4f3c\uff0c\u4f46\u4ece\u5b57\u7b26\u4e32\u7684\u53f3\u4fa7\u5f00\u59cb\u67e5\u627e\u3002\u4e0eindex()<\/code>\u4e00\u6837\uff0c\u5982\u679c\u5b50\u5b57\u7b26\u4e32\u4e0d\u5b58\u5728\uff0c\u4f1a\u5f15\u53d1ValueError<\/code>\u5f02\u5e38\u3002<\/p>\n<\/p>\n
    \u793a\u4f8b<\/h3>\n<\/p>\n
    try:<\/p>\n
        position = text.rindex("o")<\/p>\n
        print(position)  # \u8f93\u51fa: 34<\/p>\n
    except ValueError:<\/p>\n
        print("\u5b50\u5b57\u7b26\u4e32\u672a\u627e\u5230")<\/p>\n
    <\/code><\/pre>\n<\/p>\n
    \u516d\u3001STRING RFIND()\u65b9\u6cd5<\/h2>\n<\/p>\n
    rfind()<\/code>\u65b9\u6cd5\u4e0efind()<\/code>\u7c7b\u4f3c\uff0c\u4f46\u4ece\u5b57\u7b26\u4e32\u7684\u53f3\u4fa7\u5f00\u59cb\u67e5\u627e\u3002\u5b83\u8fd4\u56de\u5b50\u5b57\u7b26\u4e32\u7684\u8d77\u59cb\u7d22\u5f15\uff0c\u5982\u679c\u5b50\u5b57\u7b26\u4e32\u4e0d\u5b58\u5728\uff0c\u5219\u8fd4\u56de-1\u3002<\/p>\n<\/p>\n
    \u793a\u4f8b<\/h3>\n<\/p>\n
    position = text.rfind("o")<\/p>\n
    print(position)  # \u8f93\u51fa: 34<\/p>\n
    <\/code><\/pre>\n<\/p>\n
    \u4e03\u3001STRING STARTSWITH() \u548c ENDSWITH() \u65b9\u6cd5<\/h2>\n<\/p>\n
      \n
    • startswith()<\/strong>\uff1a\u7528\u4e8e\u68c0\u67e5\u5b57\u7b26\u4e32\u662f\u5426\u4ee5\u6307\u5b9a\u7684\u524d\u7f00\u5f00\u5934\u3002<\/li>\n
    • endswith()<\/strong>\uff1a\u7528\u4e8e\u68c0\u67e5\u5b57\u7b26\u4e32\u662f\u5426\u4ee5\u6307\u5b9a\u7684\u540e\u7f00\u7ed3\u5c3e\u3002<\/li>\n<\/ul>\n
      \u793a\u4f8b<\/h3>\n<\/p>\n
      if text.startswith("Hello"):<\/p>\n
          print("\u5b57\u7b26\u4e32\u4ee5 'Hello' \u5f00\u5934")<\/p>\n
      if text.endswith("Python."):<\/p>\n
          print("\u5b57\u7b26\u4e32\u4ee5 'Python.' \u7ed3\u5c3e")<\/p>\n
      <\/code><\/pre>\n<\/p>\n
      \u516b\u3001PERFORMANCE CONSIDERATIONS<\/h2>\n<\/p>\n
      \u5728\u5904\u7406\u5927\u5b57\u7b26\u4e32\u6216\u6267\u884c\u9891\u7e41\u7684\u67e5\u627e\u64cd\u4f5c\u65f6\uff0c\u6027\u80fd\u53ef\u80fd\u4f1a\u6210\u4e3a\u95ee\u9898\u3002\u4ee5\u4e0b\u662f\u4e00\u4e9b\u63d0\u5347\u6027\u80fd\u7684\u65b9\u6cd5\uff1a<\/p>\n<\/p>\n
        \n
      • \u4f7f\u7528\u539f\u751f\u5b57\u7b26\u4e32\u65b9\u6cd5<\/strong>\uff1afind()<\/code>\u548cindex()<\/code>\u7b49\u65b9\u6cd5\u5728\u6027\u80fd\u4e0a\u901a\u5e38\u4f18\u4e8e\u6b63\u5219\u8868\u8fbe\u5f0f\u3002<\/li>\n
      • \u9650\u5236\u641c\u7d22\u8303\u56f4<\/strong>\uff1a\u4f7f\u7528start<\/code>\u548cend<\/code>\u53c2\u6570\u9650\u5236\u641c\u7d22\u8303\u56f4\u3002<\/li>\n
      • \u907f\u514d\u4e0d\u5fc5\u8981\u7684\u64cd\u4f5c<\/strong>\uff1a\u5728\u4f7f\u7528in<\/code>\u8fd0\u7b97\u7b26\u524d\uff0c\u786e\u4fdd\u5b83\u662f\u5fc5\u8981\u7684\u3002<\/li>\n<\/ul>\n
        \u4e5d\u3001HANDLING EXCEPTIONS<\/h2>\n<\/p>\n
        \u5728\u4f7f\u7528index()<\/code>\u6216rindex()<\/code>\u65b9\u6cd5\u65f6\uff0c\u5904\u7406\u53ef\u80fd\u7684\u5f02\u5e38\u662f\u826f\u597d\u7684\u7f16\u7a0b\u5b9e\u8df5\u3002<\/p>\n<\/p>\n
        \u793a\u4f8b<\/h3>\n<\/p>\n
        try:<\/p>\n
            position = text.index("nonexistent")<\/p>\n
        except ValueError as e:<\/p>\n
            print("Error:", e)<\/p>\n
        <\/code><\/pre>\n<\/p>\n
        \u5341\u3001APPLICATIONS AND USE CASES<\/h2>\n<\/p>\n
        \u5b57\u7b26\u4e32\u67e5\u627e\u5728\u8bb8\u591a\u5e94\u7528\u7a0b\u5e8f\u4e2d\u90fd\u5f88\u91cd\u8981\uff0c\u4f8b\u5982\uff1a<\/p>\n<\/p>\n
          \n
        • \u6587\u672c\u5904\u7406<\/strong>\uff1a\u5728\u81ea\u7136\u8bed\u8a00\u5904\u7406\u4e2d\uff0c\u67e5\u627e\u7279\u5b9a\u8bcd\u6c47\u6216\u6a21\u5f0f\u662f\u5e38\u89c1\u4efb\u52a1\u3002<\/li>\n
        • \u6570\u636e\u89e3\u6790<\/strong>\uff1a\u5728\u89e3\u6790\u65e5\u5fd7\u6587\u4ef6\u6216\u6570\u636e\u6d41\u65f6\uff0c\u5b57\u7b26\u4e32\u67e5\u627e\u7528\u4e8e\u8bc6\u522b\u8bb0\u5f55\u6216\u5b57\u6bb5\u3002<\/li>\n
        • \u7528\u6237\u8f93\u5165\u9a8c\u8bc1<\/strong>\uff1a\u68c0\u67e5\u7528\u6237\u8f93\u5165\u662f\u5426\u5305\u542b\u7279\u5b9a\u7684\u5173\u952e\u8bcd\u6216\u6a21\u5f0f\u3002<\/li>\n<\/ul>\n
          \u901a\u8fc7\u7406\u89e3\u548c\u4f7f\u7528Python\u7684\u591a\u79cd\u5b57\u7b26\u4e32\u67e5\u627e\u65b9\u6cd5\uff0c\u5f00\u53d1\u8005\u53ef\u4ee5\u9ad8\u6548\u5730\u5904\u7406\u5404\u79cd\u6587\u672c\u6570\u636e\uff0c\u5e76\u89e3\u51b3\u590d\u6742\u7684\u5b57\u7b26\u4e32\u5904\u7406\u95ee\u9898\u3002<\/p>\n<\/p>\n
          \u76f8\u5173\u95ee\u7b54FAQs\uff1a<\/strong><\/h2>\n
           Python\u4e2d\u7684find\u65b9\u6cd5\u662f\u5982\u4f55\u5de5\u4f5c\u7684\uff1f<\/strong>
          \u5728Python\u4e2d\uff0cfind\u65b9\u6cd5\u7528\u4e8e\u67e5\u627e\u5b50\u5b57\u7b26\u4e32\u5728\u5b57\u7b26\u4e32\u4e2d\u7684\u4f4d\u7f6e\u3002\u5b83\u8fd4\u56de\u5b50\u5b57\u7b26\u4e32\u9996\u6b21\u51fa\u73b0\u7684\u7d22\u5f15\uff0c\u5982\u679c\u672a\u627e\u5230\uff0c\u5219\u8fd4\u56de-1\u3002\u8fd9\u4e2a\u65b9\u6cd5\u7684\u57fa\u672c\u8bed\u6cd5\u662fstr.find(substring, start, end)<\/code>\uff0c\u5176\u4e2dsubstring<\/code>\u662f\u8981\u67e5\u627e\u7684\u5b50\u5b57\u7b26\u4e32\uff0cstart<\/code>\u548cend<\/code>\u53c2\u6570\u7528\u4e8e\u6307\u5b9a\u641c\u7d22\u7684\u8303\u56f4\u3002\u4f7f\u7528find\u65b9\u6cd5\u65f6\uff0c\u53ef\u4ee5\u7075\u6d3b\u5730\u63a7\u5236\u67e5\u627e\u7684\u8d77\u59cb\u548c\u7ed3\u675f\u4f4d\u7f6e\uff0c\u5e2e\u52a9\u7528\u6237\u5728\u590d\u6742\u5b57\u7b26\u4e32\u4e2d\u66f4\u7cbe\u786e\u5730\u5b9a\u4f4d\u3002<\/p>\n
          \u5728Python\u4e2d\uff0c\u5982\u4f55\u5904\u7406find\u65b9\u6cd5\u8fd4\u56de\u7684-1\uff1f<\/strong>
          \u5f53find\u65b9\u6cd5\u8fd4\u56de-1\u65f6\uff0c\u8868\u793a\u672a\u627e\u5230\u6307\u5b9a\u7684\u5b50\u5b57\u7b26\u4e32\u3002\u4e3a\u4e86\u5904\u7406\u8fd9\u79cd\u60c5\u51b5\uff0c\u53ef\u4ee5\u4f7f\u7528\u6761\u4ef6\u8bed\u53e5\u6765\u5224\u65ad\u8fd4\u56de\u503c\u3002\u4f8b\u5982\uff0c\u53ef\u4ee5\u901a\u8fc7if<\/code>\u8bed\u53e5\u6765\u68c0\u67e5\u662f\u5426\u8fd4\u56de-1\uff0c\u5982\u679c\u662f\uff0c\u5219\u53ef\u4ee5\u8f93\u51fa\u4e00\u6761\u6d88\u606f\uff0c\u63d0\u793a\u7528\u6237\u672a\u627e\u5230\u8be5\u5b50\u5b57\u7b26\u4e32\u3002\u8fd9\u79cd\u5904\u7406\u65b9\u5f0f\u80fd\u591f\u63d0\u9ad8\u4ee3\u7801\u7684\u5065\u58ee\u6027\uff0c\u5e76\u4e3a\u7528\u6237\u63d0\u4f9b\u66f4\u597d\u7684\u53cd\u9988\u3002<\/p>\n
          \u662f\u5426\u6709\u5176\u4ed6\u65b9\u6cd5\u53ef\u4ee5\u5728Python\u4e2d\u67e5\u627e\u5b50\u5b57\u7b26\u4e32\uff1f<\/strong>
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