Python Regular Expressions

Re

Python in the RE module provides regular expression-related operations

Character:

. Match any character other than line break
\w match letters or numbers or underscores or kanji
\s matches any whitespace character
\d Matching numbers
\b Match the beginning or end of a word
^ Start of matching string
$ match End of string

Number:

* Repeat 0 or more times
+ Repeat one or more times
? Repeat 0 or one time
{n} repeats n times
{n,} repeats n or more times
{N,m} repeats n to M times

Match

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# match，从起始位置开始匹配，匹配成功返回一个对象，未匹配成功返回None match(pattern, string, flags=0) # pattern： 正则模型 # string ： 要匹配的字符串 # falgs  ： 匹配模式     X  VERBOSE     Ignore whitespace and comments for nicer looking RE‘s.     I  IGNORECASE  Perform case-insensitive matching.     M  MULTILINE   "^" matches the beginning of lines (after a newline)                    as well as the string.                    "$" matches the end of lines (before a newline) as well                    as the end of the string.     S  DOTALL      "." matches any character at all, including the newline.      A  ASCII       For string patterns, make \w, \W, \b, \B, \d, \D                    match the corresponding ASCII character categories                    (rather than the whole Unicode categories, which is the                    default).                    For bytes patterns, this flag is the only available                    behaviour and needn‘t be specified.          L  LOCALE      Make \w, \W, \b, \B, dependent on the current locale.     U  UNICODEFor compatibility only. Ignored for string patterns (it                    is the default), and forbidden for bytes patterns.

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        #  No group         r  = re.match ("h\w+",  origin)         print (R.group ())      #  get all results matching to         print (R.groups ( )     #  get the grouped results that match in the model         print ( R.groupdict ())  #  get the grouped results that match in the model         #  have groups    Why do       #  have groups? Extracts the specified content that matches successfully (first matches all the regular, then matches the successful local content extract)         r = re.match ("H (\w+). * (? p<name>\d) $ ",  origin)         print (R.group ())       #  get all results matched to         print (R.groups ())      #  get the grouped results that match in the model        &nbsP;print (R.groupdict ())  #  gets all the groups in the group that have the key executed in the model 

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Search

12	# search,浏览整个字符串去匹配第一个，未匹配成功返回None# search(pattern, string, flags=0)

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         #  No group          r = re.search ("a\w+",  origin)         print ( R.group ())      #  get all the results that match         print (R.groups ())     #  gets the grouped result         print that matches in the model ( R.groupdict ())  #  get the grouped results that match in the model         #  have groups          r = re.search ("A (\w+). * (? p<name>\d) $ ",  origin)         print (R.group ())       #  get all results matched to         print (R.groups ())      #  get the grouped results matched to in the model         print (R.groupdict ())  #  gets all the groups in the group that have executed the key in the matching group in the model 

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FindAll

123	# findall，获取非重复的匹配列表；如果有一个组则以列表形式返回，且每一个匹配均是字符串；如果模型中有多个组，则以列表形式返回，且每一个匹配均是元祖；# 空的匹配也会包含在结果中#findall(pattern, string, flags=0)

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# no grouping R = Re.findall ("a\w+", origin) print (r) # has grouping origin = "Hello Alex bcd abcd Lge ACD 19" r = Re.findall ("A ((\w*) c) (d)", origin) print (R)

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Sub

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# sub，替换匹配成功的指定位置字符串sub(pattern, repl, string, count=0, flags=0)# pattern： 正则模型# repl   ： 要替换的字符串或可执行对象# string ： 要匹配的字符串# count  ： 指定匹配个数# flags  ： 匹配模式

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# unrelated to grouping origin = "Hello Alex bcd Alex Lge" Alex ACD "r = Re.sub (" a\w+ "," 999 ", origin, 2) print (R)

Split

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# split，根据正则匹配分割字符串split(pattern, string, maxsplit=0, flags=0)# pattern： 正则模型# string ： 要匹配的字符串# maxsplit：指定分割个数# flags  ： 匹配模式

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         #  No group          origin =  "Hello alex bcd alex lge alex acd 19"          r = re.split ("Alex",  origin, 1)          print (R)         #  with group                  origin =  "Hello  alex bcd alex lge alex acd 19 "         r1 = re.split ("(Alex)",  origin, 1)          Print (R1)         r2 = re.split ("(Al (ex))",  origin,  1)         print (R2) 

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ip:^ (25[0-5]|2[0-4]\d|[ 0-1]?\d?\d) (\. ( 25[0-5]|2[0-4]\d| [0-1]?\d?\d]) {3}$ phone number: ^1[3|4|5|8][0-9]\d{8}$ mailbox: [A-za-z0-9_-][email protected][a-za-z0-9_-]+ (\.[ a-za-z0-9_-]+) +

Python Regular Expressions