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Python正則表達(dá)式的用法 [復(fù)制鏈接]

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發(fā)表于 2008-08-15 21:36 |只看該作者 |倒序?yàn)g覽
網(wǎng)上看到不錯(cuò),轉(zhuǎn)來(lái)了.
下面列出Python正則表達(dá)式的幾種匹配用法:


1.測(cè)試正則表達(dá)式是否匹配字符串的全部或部分
regex=ur"" #正則表達(dá)式
if re.search(regex, subject):
    do_something()
else:
    do_anotherthing()


2.測(cè)試正則表達(dá)式是否匹配整個(gè)字符串
regex=ur"\Z" #正則表達(dá)式末尾以\Z結(jié)束
if re.match(regex, subject):
    do_something()
else:
    do_anotherthing()


3.創(chuàng)建一個(gè)匹配對(duì)象,然后通過(guò)該對(duì)象獲得匹配細(xì)節(jié)(Create an object with details about how the regex matches (part of) a string)
regex=ur"" #正則表達(dá)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()


4.獲取正則表達(dá)式所匹配的子串(Get the part of a string matched by the regex)
regex=ur"" #正則表達(dá)式
match = re.search(regex, subject)
if match:
    result = match.group()
else:
    result = ""


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(dá)式
match = re.search(regex, subject)
if match:
    result = match.group(1)
else:
    result = ""


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(dá)式
match = re.search(regex, subject)
if match:
    result = match.group"groupname")
else:
    result = ""


7. 將字符串中所有匹配的子串放入數(shù)組中(Get an array of all regex matches in a string)
result = re.findall(regex, subject)


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)
&nbsp;&nbsp;&nbsp;&nbsp;# match start: match.start()
&nbsp;&nbsp;&nbsp;&nbsp;# match end (exclusive): atch.end()
&nbsp;&nbsp;&nbsp;&nbsp;# matched text: match.group()


9.通過(guò)正則表達(dá)式字符串創(chuàng)建一個(gè)正則表達(dá)式對(duì)象(Create an object to use the same regex for many operations)
reobj = re.compile(regex)


10.用法1的正則表達(dá)式對(duì)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):
&nbsp;&nbsp;&nbsp;&nbsp;do_something()
else:
&nbsp;&nbsp;&nbsp;&nbsp;do_anotherthing()


11.用法2的正則表達(dá)式對(duì)象版本(use regex object for if/else branch whether a string can be matched entirely)
reobj = re.compile(r"\Z")。U齽t表達(dá)式末尾以\Z 結(jié)束
if reobj.match(subject):
&nbsp;&nbsp;&nbsp;&nbsp;do_something()
else:
&nbsp;&nbsp;&nbsp;&nbsp;do_anotherthing()


12.創(chuàng)建一個(gè)正則表達(dá)式對(duì)象,然后通過(guò)該對(duì)象獲得匹配細(xì)節(jié)(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:
&nbsp;&nbsp;&nbsp;&nbsp;# match start: match.start()
&nbsp;&nbsp;&nbsp;&nbsp;# match end (exclusive): atch.end()
&nbsp;&nbsp;&nbsp;&nbsp;# matched text: match.group()
&nbsp;&nbsp;&nbsp;&nbsp;do_something()
else:
&nbsp;&nbsp;&nbsp;&nbsp;do_anotherthing()


13.用正則表達(dá)式對(duì)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:
&nbsp;&nbsp;&nbsp;&nbsp;result = match.group()
else:
&nbsp;&nbsp;&nbsp;&nbsp;result = ""


14.用正則表達(dá)式對(duì)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:
&nbsp;&nbsp;&nbsp;&nbsp;result = match.group(1)
else:
&nbsp;&nbsp;&nbsp;&nbsp;result = ""


15.用正則表達(dá)式對(duì)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:
&nbsp;&nbsp;&nbsp;&nbsp;result = match.group("groupname")
else:
&nbsp;&nbsp;&nbsp;&nbsp;result = ""


16.用正則表達(dá)式對(duì)象獲取所有匹配子串并放入數(shù)組(Use regex object to get an array of all regex matches in a string)
reobj = re.compile(regex)
result = reobj.findall(subject)


17.通過(guò)正則表達(dá)式對(duì)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):
&nbsp;&nbsp;&nbsp;&nbsp;# match start: match.start()
&nbsp;&nbsp;&nbsp;&nbsp;# match end (exclusive): match.end()
&nbsp;&nbsp;&nbsp;&nbsp;# matched text: match.group()





字符串替換

1.替換所有匹配的子串
#用newstring替換subject中所有與正則表達(dá)式regex匹配的子串
result = re.sub(regex, newstring, subject)


2.替換所有匹配的子串(使用正則表達(dá)式對(duì)象)
reobj = re.compile(regex)
result = reobj.sub(newstring, subject)


字符串拆分

1.字符串拆分
result = re.split(regex, subject)


2.字符串拆分(使用正則表示式對(duì)象)
reobj = re.compile(regex)
result = reobj.split(subject)

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2 [報(bào)告]
發(fā)表于 2008-08-15 21:38 |只看該作者
謝謝!

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3 [報(bào)告]
發(fā)表于 2008-08-15 23:10 |只看該作者
mark

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4 [報(bào)告]
發(fā)表于 2008-08-15 23:21 |只看該作者
good

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5 [報(bào)告]
發(fā)表于 2008-08-16 15:28 |只看該作者
木有perl來(lái)的方便
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