David Dong

Java/C/C#/Python

POST

Python re module

May 11, 2019

re module is a unique string matching module of Python.

Many functions provided in this module are implemented based on regular expressions.

The module is handy, to use it, need to import re module at first.

prototype

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

parameters

pattern: Separator, can be character or regular expression.
string: String to split.
maxsplit: Maximum number of split. default is 0, which means no limitation. if minus, means no split.
flags: Used to control how regular expressions are matched.

examples

split the input string by space and ,, only do one time split.

import re
inputs = re.split(r'[\s,]+', input("Enter: 'ID' ['File name'] >> "), 1)
Enter: 'ID' ['File name'] >> 01 filename
inputs
['01', 'filename']
inputs = re.split(r'[\s,]+', input("Enter: 'ID' ['File name'] >> "), 1)
Enter: 'ID' ['File name'] >> 01,filename
inputs
['01', 'filename']
inputs = re.split(r'[\s,]+', input("Enter: 'ID' ['File name'] >> "), 1)
Enter: 'ID' ['File name'] >> 01,file1,file2 file3
inputs
['01', 'file1,file2 file3']

split the string by character.

import re
s = 'ab12,% ffa[]-(fceknl)'
re.split(r'b',s)
['a', '12,% ffa[]-(fceknl)']
re.split(r'f',s)
['ab12,% ', '', 'a[]-(', 'ceknl)']

match multiple characters

import re
s = 'ab12,% ffa[]-(fceknl)'
re.split(r'[1,en]',s)
['ab', '2', '% ffa[]-(fc', 'k', 'l)']
re.split(r'[-e(n]',s)
['ab12,% ffa[]', '', 'fc', 'k', 'l)']

keep separator

import re
s = 'ab12,% ffa[]-(fceknl)'
re.split('([af])',s)
['', 'a', 'b12,% ', 'f', '', 'f', '', 'a', '[]-(', 'f', 'ceknl)']

Python