Some methods of re

1. re.compile(pattern, flags=0)

   Create a reusable variable from a regular expression.

   The generated object can be used in other places repeatedly, instead of generating the same expression again every time it is passed.

   The flags parameter will be described later. Multiple can be declared with |

   import re regex = re.compile("\\w+") ret = re.findall(regex,"afsd fasd11as 22d") print(ret) ret = re.findall(regex,"afsd fasd112as 223as") print(ret)

2. flags
   • re.A re.ASCII

     Match only ascii, not unicode.

   • re.I re.IGNORECASE

     Ignore case matching

     import re regex = re.compile("[A-Z]+",re.I) ret = re.findall(regex,"afsd fasd11as 22d") print(ret) ret = re.findall(regex,"afsd fasd112as 223as") print(ret)

   • re.M re.MULTILINE

     This will affect the matching of ^ $, as well as the parsing mode

     import re data = """ asdfd asdfas basdfdsaf aa asada """ regex = re.compile("^[A-Z]+$",re.I|re.MULTILINE) ret = re.findall(regex,data) print(ret) ret = re.findall(regex,data) print(ret)

   • re.S re.DOTALL

     Match all characters including line breaks

     import re data = """ asdfd asdfas basdfdsaf aa asada """ ret = re.findall("^.+$",data,re.I|re.S) print(ret) ret = re.findall("^.+$",data,re.I) print(ret)

3. re.search(pattern, string, flags=0)

   Find the first one that meets the rule and return a match object

   re.findall is a search for all matching strings, and re.match is a match from scratch.

   import re data = """ asdfd asdfas basdfdsaf aa asada """ ret = re.search("^.+$",data,re.I|re.S) print(ret)

4. re.match(pattern, string, flags=0)

   It is related to or * or? If the match length is 0, there is a match

   There is a difference between a mismatch and a match with a length of 0. A match with a length of 0 means that your rule allows a match with a length of 0

   import re data = """ asdfd asdfas basdfdsaf aa asada """ ret = re.match("^.+$",data,re.I|re.S) print(ret) ret = re.match(".*",data) print(ret)

5. re.fullmatch(pattern, string, flags=0)

   Strictly match from beginning to end, slightly.

6. re.split(pattern, string, maxsplit=0, flags=0)

   The maximum number of maxplits is separated according to the separation rule pattern. Maxplit = 0 means to separate all

   import re data = """ asdfd asdfas basdfdsaf aa asada """ ret = re.split("\n",data,re.I|re.S) print(ret)

7. re.findall(pattern, string, flags=0)

   Returns a string set that is not repeated. This string is scanned from left to right. All matched strings are stored in order. If there are groups, they are stored in the form of tuples. If there is no match, they are returned as empty sets.

   A tuple is a string '' and a tuple is a tuple type ('', ''). The first is where the first left bracket appears, and the brackets are paired.

   • Monadic group

     import re data = """ asdfd asdfas basdfdsaf aa asada """ ret = re.findall("a(\\w+)d",data,re.I|re.S) print(ret)

   • Two tuple

     import re data = """ asdfd asdfas basdfdsaf aa asada """ ret = re.findall("(a(\\w+)d)",data,re.I|re.S) print(ret)

8. re.finditer(pattern, string, flags=0)

   Returned as an iterator.

   import re data = """ asdfd asdfas basdfdsaf aa asada """ ret = re.finditer("(a(\\w+)d)",data,re.I|re.S) print(ret) for i in ret: print(i.groups())

9. re.sub(pattern, repl, string, count=0, flags=0)
   • Pattern: string or regex
   • Repl: string or a method that accepts a parameter. The parameter passed in is a match object
   • String: scan string
   • count: the maximum number of substitutions. 0 means all
   • Flags: additional parsing flags, Reference link.

   Returns the replaced string. repl can contain groups.

   • String substitution

     import re data = """ asdfd asdfas basdfdsaf aa asada """ ret = re.sub("(a(\\w+)d)","regex",data,re.I|re.S) print(ret)

   • Method substitution

     import re data = """ asdfd asdfas basdfdsaf aa asada """ ret = re.sub("a(\\w+)d",lambda a: a.group()[1:-1],data,re.I|re.S) print(ret)

   • Group replacement

     import re data = """ asdfd asdfas basdfdsaf aa asada """ ret = re.sub("a(\\w+)d","\\1",data,re.I|re.S) print(ret)

10. re.escape(pattern)

    Pass in a string and return the regex object of the string. And will have a special meaning in the regular expression character escape.

    import re data = """..""" ret = re.escape(data) print(ret)

4 December 2019, 08:54 | Views: 1897