{"id":1101856,"date":"2025-01-08T15:53:57","date_gmt":"2025-01-08T07:53:57","guid":{"rendered":"https:\/\/docs.pingcode.com\/ask\/ask-ask\/1101856.html"},"modified":"2025-01-08T15:54:01","modified_gmt":"2025-01-08T07:54:01","slug":"python3%e5%a6%82%e4%bd%95%e6%9f%a5%e6%89%be%e5%ad%97%e7%ac%a6%e4%b8%b2-2","status":"publish","type":"post","link":"https:\/\/docs.pingcode.com\/ask\/1101856.html","title":{"rendered":"python3\u5982\u4f55\u67e5\u627e\u5b57\u7b26\u4e32"},"content":{"rendered":"

\"python3\u5982\u4f55\u67e5\u627e\u5b57\u7b26\u4e32\"<\/p>\n

Python3\u67e5\u627e\u5b57\u7b26\u4e32\u7684\u65b9\u6cd5\u6709\u591a\u79cd\uff0c\u5305\u62ec\u4f7f\u7528find()\u65b9\u6cd5\u3001index()\u65b9\u6cd5\u3001\u6b63\u5219\u8868\u8fbe\u5f0f\u7b49\u3002\u6bcf\u79cd\u65b9\u6cd5\u90fd\u6709\u5176\u72ec\u7279\u7684\u4f18\u70b9\u548c\u9002\u7528\u573a\u666f\u3002<\/strong>\u5176\u4e2d\uff0cfind()\u65b9\u6cd5\u662f\u6700\u5e38\u7528\u7684\u4e00\u79cd\uff0c\u56e0\u4e3a\u5b83\u7b80\u5355\u6613\u7528\u4e14\u6548\u7387\u8f83\u9ad8\u3002\u4f7f\u7528find()\u65b9\u6cd5\u65f6\uff0c\u5982\u679c\u627e\u5230\u6307\u5b9a\u7684\u5b50\u5b57\u7b26\u4e32\uff0c\u5b83\u4f1a\u8fd4\u56de\u5b50\u5b57\u7b26\u4e32\u7684\u8d77\u59cb\u4f4d\u7f6e\u7d22\u5f15\uff1b\u5982\u679c\u6ca1\u6709\u627e\u5230\uff0c\u5219\u8fd4\u56de-1\u3002\u5177\u4f53\u4f7f\u7528\u65b9\u6cd5\u5982\u4e0b\uff1a<\/p>\n<\/p>\n

text = "Hello, welcome to the world of Python"<\/p>\n
position = text.find("world")<\/p>\n
print(position)  # \u8f93\u51fa\uff1a21<\/p>\n
<\/code><\/pre>\n<\/p>\n
\u53e6\u5916\uff0cindex()\u65b9\u6cd5\u4e0efind()\u65b9\u6cd5\u7c7b\u4f3c\uff0c\u4f46\u5982\u679c\u672a\u627e\u5230\u5b50\u5b57\u7b26\u4e32\uff0c\u5b83\u4f1a\u629b\u51fa\u4e00\u4e2aValueError\u5f02\u5e38\u3002\u6b63\u5219\u8868\u8fbe\u5f0f\u5219\u9002\u7528\u4e8e\u66f4\u590d\u6742\u7684\u5b57\u7b26\u4e32\u67e5\u627e\u9700\u6c42\uff0c\u80fd\u591f\u8fdb\u884c\u6a21\u5f0f\u5339\u914d\u3002\u4ee5\u4e0b\u662f\u5bf9find()\u65b9\u6cd5\u7684\u8be6\u7ec6\u63cf\u8ff0\u3002<\/p>\n<\/p>\n
\u4e00\u3001find()\u65b9\u6cd5<\/h3>\n<\/p>\n
find()\u65b9\u6cd5\u662fPython\u4e2d\u67e5\u627e\u5b57\u7b26\u4e32\u6700\u5e38\u89c1\u7684\u65b9\u5f0f\u4e4b\u4e00\u3002\u5b83\u7528\u4e8e\u5728\u5b57\u7b26\u4e32\u4e2d\u67e5\u627e\u6307\u5b9a\u7684\u5b50\u5b57\u7b26\u4e32\uff0c\u5982\u679c\u627e\u5230\u5219\u8fd4\u56de\u5b50\u5b57\u7b26\u4e32\u7684\u8d77\u59cb\u4f4d\u7f6e\u7d22\u5f15\uff0c\u5426\u5219\u8fd4\u56de-1\u3002<\/p>\n<\/p>\n
text = "Hello, welcome to the world of Python"<\/p>\n
position = text.find("world")<\/p>\n
print(position)  # \u8f93\u51fa\uff1a21<\/p>\n
<\/code><\/pre>\n<\/p>\n
find()\u65b9\u6cd5\u8fd8\u53ef\u4ee5\u63a5\u53d7\u4e24\u4e2a\u53ef\u9009\u53c2\u6570\uff0cstart\u548cend\uff0c\u7528\u4e8e\u6307\u5b9a\u67e5\u627e\u7684\u8d77\u59cb\u548c\u7ed3\u675f\u4f4d\u7f6e\u3002<\/p>\n<\/p>\n
text = "Hello, welcome to the world of Python"<\/p>\n
position = text.find("world", 10, 30)<\/p>\n
print(position)  # \u8f93\u51fa\uff1a21<\/p>\n
<\/code><\/pre>\n<\/p>\n
\u4e8c\u3001index()\u65b9\u6cd5<\/h3>\n<\/p>\n
index()\u65b9\u6cd5\u4e0efind()\u65b9\u6cd5\u7c7b\u4f3c\uff0c\u4f46\u5982\u679c\u5b50\u5b57\u7b26\u4e32\u672a\u627e\u5230\uff0c\u5b83\u4f1a\u629b\u51fa\u4e00\u4e2aValueError\u5f02\u5e38\u3002\u8fd9\u5728\u9700\u8981\u786e\u4fdd\u5b50\u5b57\u7b26\u4e32\u5b58\u5728\u65f6\u975e\u5e38\u6709\u7528\u3002<\/p>\n<\/p>\n
text = "Hello, welcome to the world of Python"<\/p>\n
try:<\/p>\n
    position = text.index("world")<\/p>\n
    print(position)  # \u8f93\u51fa\uff1a21<\/p>\n
except ValueError:<\/p>\n
    print("\u5b50\u5b57\u7b26\u4e32\u672a\u627e\u5230")<\/p>\n
<\/code><\/pre>\n<\/p>\n
\u4e09\u3001\u6b63\u5219\u8868\u8fbe\u5f0f<\/h3>\n<\/p>\n
\u6b63\u5219\u8868\u8fbe\u5f0f\u63d0\u4f9b\u4e86\u66f4\u5f3a\u5927\u7684\u5b57\u7b26\u4e32\u67e5\u627e\u529f\u80fd\uff0c\u80fd\u591f\u8fdb\u884c\u590d\u6742\u7684\u6a21\u5f0f\u5339\u914d\u3002Python\u7684re\u6a21\u5757\u63d0\u4f9b\u4e86\u4e30\u5bcc\u7684\u6b63\u5219\u8868\u8fbe\u5f0f\u652f\u6301\u3002<\/p>\n<\/p>\n
import re<\/p>\n
text = "Hello, welcome to the world of Python"<\/p>\n
pattern = re.compile(r"world")<\/p>\n
match = pattern.search(text)<\/p>\n
if match:<\/p>\n
    print(match.start())  # \u8f93\u51fa\uff1a21<\/p>\n
<\/code><\/pre>\n<\/p>\n
\u56db\u3001count()\u65b9\u6cd5<\/h3>\n<\/p>\n
count()\u65b9\u6cd5\u7528\u4e8e\u7edf\u8ba1\u5b50\u5b57\u7b26\u4e32\u5728\u5b57\u7b26\u4e32\u4e2d\u51fa\u73b0\u7684\u6b21\u6570\u3002\u867d\u7136\u5b83\u4e0d\u8fd4\u56de\u5b50\u5b57\u7b26\u4e32\u7684\u4f4d\u7f6e\uff0c\u4f46\u5728\u9700\u8981\u4e86\u89e3\u5b50\u5b57\u7b26\u4e32\u51fa\u73b0\u9891\u7387\u65f6\u975e\u5e38\u6709\u7528\u3002<\/p>\n<\/p>\n
text = "Hello, welcome to the world of Python. Python is great!"<\/p>\n
count = text.count("Python")<\/p>\n
print(count)  # \u8f93\u51fa\uff1a2<\/p>\n
<\/code><\/pre>\n<\/p>\n
\u4e94\u3001\u4f7f\u7528in\u8fd0\u7b97\u7b26<\/h3>\n<\/p>\n
in\u8fd0\u7b97\u7b26\u53ef\u4ee5\u7528\u4e8e\u68c0\u67e5\u5b50\u5b57\u7b26\u4e32\u662f\u5426\u5b58\u5728\u4e8e\u5b57\u7b26\u4e32\u4e2d\uff0c\u5b83\u8fd4\u56de\u4e00\u4e2a\u5e03\u5c14\u503c\u3002\u867d\u7136\u5b83\u4e0d\u63d0\u4f9b\u5b50\u5b57\u7b26\u4e32\u7684\u4f4d\u7f6e\uff0c\u4f46\u5728\u9700\u8981\u7b80\u5355\u5b58\u5728\u6027\u68c0\u67e5\u65f6\u975e\u5e38\u65b9\u4fbf\u3002<\/p>\n<\/p>\n
text = "Hello, welcome to the world of Python"<\/p>\n
exists = "world" in text<\/p>\n
print(exists)  # \u8f93\u51fa\uff1aTrue<\/p>\n
<\/code><\/pre>\n<\/p>\n
\u516d\u3001startswith()\u548cendswith()\u65b9\u6cd5<\/h3>\n<\/p>\n
startswith()\u548cendswith()\u65b9\u6cd5\u7528\u4e8e\u68c0\u67e5\u5b57\u7b26\u4e32\u662f\u5426\u4ee5\u6307\u5b9a\u7684\u5b50\u5b57\u7b26\u4e32\u5f00\u5934\u6216\u7ed3\u5c3e\u3002\u8fd9\u5bf9\u4e8e\u7279\u5b9a\u6a21\u5f0f\u7684\u5339\u914d\u975e\u5e38\u6709\u7528\u3002<\/p>\n<\/p>\n
text = "Hello, welcome to the world of Python"<\/p>\n
starts_with = text.startswith("Hello")<\/p>\n
print(starts_with)  # \u8f93\u51fa\uff1aTrue<\/p>\n
ends_with = text.endswith("Python")<\/p>\n
print(ends_with)  # \u8f93\u51fa\uff1aTrue<\/p>\n
<\/code><\/pre>\n<\/p>\n
\u4e03\u3001\u67e5\u627e\u591a\u4e2a\u5b50\u5b57\u7b26\u4e32<\/h3>\n<\/p>\n
\u6709\u65f6\u6211\u4eec\u9700\u8981\u5728\u5b57\u7b26\u4e32\u4e2d\u67e5\u627e\u591a\u4e2a\u5b50\u5b57\u7b26\u4e32\uff0c\u4f7f\u7528\u5b57\u5178\u53ef\u4ee5\u65b9\u4fbf\u5730\u8bb0\u5f55\u6bcf\u4e2a\u5b50\u5b57\u7b26\u4e32\u7684\u8d77\u59cb\u4f4d\u7f6e\u3002<\/p>\n<\/p>\n
text = "Hello, welcome to the world of Python"<\/p>\n
substrings = ["Hello", "world", "Python"]<\/p>\n
positions = {substr: text.find(substr) for substr in substrings}<\/p>\n
print(positions)  # \u8f93\u51fa\uff1a{'Hello': 0, 'world': 21, 'Python': 31}<\/p>\n
<\/code><\/pre>\n<\/p>\n
\u516b\u3001\u5b57\u7b26\u4e32\u5207\u7247\u4e0e\u67e5\u627e\u7ed3\u5408<\/h3>\n<\/p>\n
\u901a\u8fc7\u7ed3\u5408\u5b57\u7b26\u4e32\u5207\u7247\u548c\u67e5\u627e\u65b9\u6cd5\uff0c\u53ef\u4ee5\u5b9e\u73b0\u66f4\u7075\u6d3b\u7684\u5b57\u7b26\u4e32\u64cd\u4f5c\u3002\u4f8b\u5982\uff0c\u53ef\u4ee5\u5728\u627e\u5230\u5b50\u5b57\u7b26\u4e32\u540e\u622a\u53d6\u7279\u5b9a\u8303\u56f4\u7684\u5185\u5bb9\u3002<\/p>\n<\/p>\n
text = "Hello, welcome to the world of Python"<\/p>\n
position = text.find("world")<\/p>\n
if position != -1:<\/p>\n
    snippet = text[position:position + 5]  # \u622a\u53d6"world"<\/p>\n
    print(snippet)  # \u8f93\u51fa\uff1aworld<\/p>\n
<\/code><\/pre>\n<\/p>\n
\u4e5d\u3001\u81ea\u5b9a\u4e49\u67e5\u627e\u51fd\u6570<\/h3>\n<\/p>\n
\u5728\u67d0\u4e9b\u60c5\u51b5\u4e0b\uff0c\u5185\u7f6e\u65b9\u6cd5\u53ef\u80fd\u65e0\u6cd5\u5b8c\u5168\u6ee1\u8db3\u9700\u6c42\uff0c\u53ef\u4ee5\u7f16\u5199\u81ea\u5b9a\u4e49\u51fd\u6570\u6765\u5b9e\u73b0\u66f4\u590d\u6742\u7684\u67e5\u627e\u903b\u8f91\u3002\u4f8b\u5982\uff0c\u67e5\u627e\u6240\u6709\u51fa\u73b0\u4f4d\u7f6e\u3002<\/p>\n<\/p>\n
def find_all_occurrences(text, substring):<\/p>\n
    start = 0<\/p>\n
    positions = []<\/p>\n
    while start < len(text):<\/p>\n
        position = text.find(substring, start)<\/p>\n
        if position == -1:<\/p>\n
            break<\/p>\n
        positions.append(position)<\/p>\n
        start = position + 1<\/p>\n
    return positions<\/p>\n
text = "Hello, welcome to the world of Python. Python is great!"<\/p>\n
positions = find_all_occurrences(text, "Python")<\/p>\n
print(positions)  # \u8f93\u51fa\uff1a[31, 39]<\/p>\n
<\/code><\/pre>\n<\/p>\n
\u5341\u3001\u6027\u80fd\u4f18\u5316<\/h3>\n<\/p>\n
\u5728\u5904\u7406\u5927\u6587\u672c\u6216\u9891\u7e41\u67e5\u627e\u64cd\u4f5c\u65f6\uff0c\u6027\u80fd\u4f18\u5316\u663e\u5f97\u5c24\u4e3a\u91cd\u8981\u3002\u53ef\u4ee5\u901a\u8fc7\u4ee5\u4e0b\u51e0\u79cd\u65b9\u5f0f\u63d0\u5347\u6027\u80fd\uff1a<\/p>\n<\/p>\n
    \n
  1. \u7f13\u5b58\u7ed3\u679c<\/strong>\uff1a\u5bf9\u4e8e\u91cd\u590d\u67e5\u627e\u7684\u5b50\u5b57\u7b26\u4e32\uff0c\u53ef\u4ee5\u7f13\u5b58\u67e5\u627e\u7ed3\u679c\uff0c\u907f\u514d\u91cd\u590d\u8ba1\u7b97\u3002<\/li>\n
  2. \u4f7f\u7528\u5408\u9002\u7684\u6570\u636e\u7ed3\u6784<\/strong>\uff1a\u5728\u67d0\u4e9b\u573a\u666f\u4e0b\uff0c\u4f7f\u7528\u66f4\u9ad8\u6548\u7684\u6570\u636e\u7ed3\u6784\uff08\u5982Trie\u6811\uff09\u53ef\u4ee5\u63d0\u5347\u67e5\u627e\u6548\u7387\u3002<\/li>\n
  3. \u5e76\u884c\u5904\u7406<\/strong>\uff1a\u5728\u591a\u6838\u5904\u7406\u5668\u4e0a\uff0c\u53ef\u4ee5\u5229\u7528\u591a\u7ebf\u7a0b\u6216\u591a\u8fdb\u7a0b\u5e76\u884c\u67e5\u627e\uff0c\u63d0\u9ad8\u5904\u7406\u901f\u5ea6\u3002<\/li>\n<\/ol>\n
    # \u793a\u4f8b\uff1a\u4f7f\u7528\u7f13\u5b58\u63d0\u5347\u67e5\u627e\u6027\u80fd<\/p>\n
    cache = {}<\/p>\n
    def find_with_cache(text, substring):<\/p>\n
        if substring in cache:<\/p>\n
            return cache[substring]<\/p>\n
        position = text.find(substring)<\/p>\n
        cache[substring] = position<\/p>\n
        return position<\/p>\n
    text = "Hello, welcome to the world of Python"<\/p>\n
    position = find_with_cache(text, "world")<\/p>\n
    print(position)  # \u8f93\u51fa\uff1a21<\/p>\n
    <\/code><\/pre>\n<\/p>\n
    \u901a\u8fc7\u4e86\u89e3\u548c\u638c\u63e1\u4e0a\u8ff0\u5404\u79cd\u67e5\u627e\u65b9\u6cd5\u53ca\u5176\u5e94\u7528\u573a\u666f\uff0c\u53ef\u4ee5\u5728\u5b9e\u9645\u7f16\u7a0b\u4e2d\u7075\u6d3b\u9009\u62e9\u5408\u9002\u7684\u5de5\u5177\uff0c\u63d0\u5347\u4ee3\u7801\u7684\u53ef\u8bfb\u6027\u548c\u8fd0\u884c\u6548\u7387\u3002\u65e0\u8bba\u662f\u7b80\u5355\u7684\u67e5\u627e\u9700\u6c42\u8fd8\u662f\u590d\u6742\u7684\u6a21\u5f0f\u5339\u914d\uff0cPython\u90fd\u63d0\u4f9b\u4e86\u4e30\u5bcc\u7684\u89e3\u51b3\u65b9\u6848\u3002<\/p>\n<\/p>\n
    \u76f8\u5173\u95ee\u7b54FAQs\uff1a<\/strong><\/h2>\n
     \u5982\u4f55\u5728Python3\u4e2d\u67e5\u627e\u5b57\u7b26\u4e32\u7684\u7279\u5b9a\u5b50\u4e32\uff1f<\/strong>
    \u5728Python3\u4e2d\uff0c\u53ef\u4ee5\u4f7f\u7528str.find()<\/code>\u6216str.index()<\/code>\u65b9\u6cd5\u6765\u67e5\u627e\u5b57\u7b26\u4e32\u4e2d\u7684\u7279\u5b9a\u5b50\u4e32\u3002find()<\/code>\u65b9\u6cd5\u8fd4\u56de\u5b50\u4e32\u7684\u8d77\u59cb\u7d22\u5f15\uff0c\u5982\u679c\u672a\u627e\u5230\u5219\u8fd4\u56de-1\uff1b\u800cindex()<\/code>\u65b9\u6cd5\u5728\u672a\u627e\u5230\u65f6\u4f1a\u5f15\u53d1ValueError<\/code>\u5f02\u5e38\u3002\u6b64\u5916\uff0cstr.contAI<\/a>ns()<\/code>\u65b9\u6cd5\u548c\u6b63\u5219\u8868\u8fbe\u5f0f\u4e5f\u53ef\u4ee5\u7528\u4e8e\u66f4\u590d\u6742\u7684\u67e5\u627e\u3002<\/p>\n
    Python3\u4e2d\u6709\u54ea\u4e9b\u65b9\u6cd5\u53ef\u4ee5\u8fdb\u884c\u5b57\u7b26\u4e32\u7684\u6a21\u7cca\u67e5\u627e\uff1f<\/strong>
    \u5982\u679c\u9700\u8981\u8fdb\u884c\u6a21\u7cca\u67e5\u627e\uff0c\u53ef\u4ee5\u4f7f\u7528\u6b63\u5219\u8868\u8fbe\u5f0f\u6a21\u5757re<\/code>\u3002\u4f8b\u5982\uff0cre.search()<\/code>\u53ef\u4ee5\u7528\u6765\u67e5\u627e\u7b26\u5408\u7279\u5b9a\u6a21\u5f0f\u7684\u5b57\u7b26\u4e32\uff0c\u65e0\u8bba\u5176\u4f4d\u7f6e\u5982\u4f55\u3002\u6b64\u5916\uff0cstr.lower()<\/code>\u548cstr.upper()<\/code>\u65b9\u6cd5\u53ef\u4ee5\u5e2e\u52a9\u5b9e\u73b0\u4e0d\u533a\u5206\u5927\u5c0f\u5199\u7684\u67e5\u627e\u3002<\/p>\n
    \u5982\u4f55\u5728Python3\u4e2d\u67e5\u627e\u5b57\u7b26\u4e32\u7684\u6240\u6709\u51fa\u73b0\u4f4d\u7f6e\uff1f<\/strong>
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