Python正則表達式的用法
- 2020 年 1 月 9 日
- 筆記
網上看到不錯,轉來了.
下面列出Python正則表達式的幾種匹配用法：
1.測試正則表達式是否匹配字元串的全部或部分
regex=ur"" #正則表達式if re.search(regex, subject): do_something()else: do_anotherthing() |
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2.測試正則表達式是否匹配整個字元串
regex=ur"Z" #正則表達式末尾以Z結束if re.match(regex, subject): do_something()else: do_anotherthing() |
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3.創建一個匹配對象，然後通過該對象獲得匹配細節(Create an object with details about how the regex matches (part of) a string)
regex=ur"" #正則表達式 match = re.search(regex, subject)if match: # match start: match.start() # match end (exclusive): atch.end() # matched text: match.group() do_something()else: do_anotherthing() |
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4.獲取正則表達式所匹配的子串(Get the part of a string matched by the regex)
regex=ur"" #正則表達式 match = re.search(regex, subject)if match: result = match.group()else: result = "" |
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5. 獲取捕獲組所匹配的子串(Get the part of a string matched by a capturing group)
regex=ur"" #正則表達式 match = re.search(regex, subject)if match: result = match.group(1)else: result = "" |
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6. 獲取有名組所匹配的子串(Get the part of a string matched by a named group)
regex=ur"" #正則表達式 match = re.search(regex, subject) if match: result = match.group"groupname") else: result = "" |
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7. 將字元串中所有匹配的子串放入數組中(Get an array of all regex matches in a string)
result = re.findall(regex, subject) |
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8.遍歷所有匹配的子串(Iterate over all matches in a string)
for match in re.finditer(r"<(.*?)s*.*?/1>", subject) # match start: match.start() # match end (exclusive): atch.end() # matched text: match.group() |
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9.通過正則表達式字元串創建一個正則表達式對象(Create an object to use the same regex for many operations)
reobj = re.compile(regex) |
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10.用法１的正則表達式對象版本（use regex object for if/else branch whether (part of) a string can be matched）
reobj = re.compile(regex)if reobj.search(subject): do_something()else: do_anotherthing() |
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11.用法２的正則表達式對象版本（use regex object for if/else branch whether a string can be matched entirely）
reobj = re.compile(r"Z") ＃正則表達式末尾以Z 結束if reobj.match(subject): do_something()else: do_anotherthing() |
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12.創建一個正則表達式對象，然後通過該對象獲得匹配細節（Create an object with details about how the regex object matches (part of) a string）
reobj = re.compile(regex) match = reobj.search(subject)if match: # match start: match.start() # match end (exclusive): atch.end() # matched text: match.group() do_something()else: do_anotherthing() |
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13.用正則表達式對象獲取匹配子串（Use regex object to get the part of a string matched by the regex）
reobj = re.compile(regex) match = reobj.search(subject)if match: result = match.group()else: result = "" |
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14.用正則表達式對象獲取捕獲組所匹配的子串（Use regex object to get the part of a string matched by a capturing group）
reobj = re.compile(regex) match = reobj.search(subject)if match: result = match.group(1)else: result = "" |
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15.用正則表達式對象獲取有名組所匹配的子串（Use regex object to get the part of a string matched by a named group）
reobj = re.compile(regex) match = reobj.search(subject)if match: result = match.group("groupname")else: result = "" |
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16.用正則表達式對象獲取所有匹配子串並放入數組（Use regex object to get an array of all regex matches in a string）
reobj = re.compile(regex) result = reobj.findall(subject) |
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17.通過正則表達式對象遍歷所有匹配子串（Use regex object to iterate over all matches in a string）
reobj = re.compile(regex)for match in reobj.finditer(subject): # match start: match.start() # match end (exclusive): match.end() # matched text: match.group() |
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字元串替換
1.替換所有匹配的子串
#用newstring替換subject中所有與正則表達式regex匹配的子串 result = re.sub(regex, newstring, subject) |
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2.替換所有匹配的子串（使用正則表達式對象）
reobj = re.compile(regex) result = reobj.sub(newstring, subject) |
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字元串拆分
1.字元串拆分
result = re.split(regex, subject) |
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2.字元串拆分（使用正則表示式對象）
reobj=re.compile(regex)
result=reobj.split(subject)