The re
module in Python provides a powerful set of tools for working with regular expressions, allowing you to perform complex string operations such as searching, matching, and replacing text patterns. This module is essential for advanced text processing and manipulation tasks.
Key Functions of the **re**
Module
**re.match(pattern, string)**
Checks if the pattern matches at the beginning of the string.
**re.search(pattern, string)**
Searches for the first occurrence of the pattern anywhere in the string.
re.search()
returns a match object for the first occurrence of the pattern.**re.findall(pattern, string)**
Returns a list of all non-overlapping matches of the pattern in the string.
**re.finditer(pattern, string)**
Returns an iterator yielding match objects for all non-overlapping matches of the pattern.
re.finditer()
provides match objects, which can be useful for more detailed information about each match.**re.sub(pattern, repl, string)**
Replaces occurrences of the pattern in the string with a replacement substring.
"NUMBER"
.**re.split(pattern, string)**
Splits the string by occurrences of the pattern.
Regular Expression Patterns
r'abc'
matches the substring "abc"
..
, ^
, $
, *
, +
, ?
, []
, |
, ()
.
.
: Matches any character except a newline.^
: Matches the start of the string.$
: Matches the end of the string.*
: Matches 0 or more repetitions of the preceding character.+
: Matches 1 or more repetitions of the preceding character.?
: Matches 0 or 1 repetition of the preceding character.[]
: Matches any one of the characters inside the brackets.|
: Acts as a logical OR between two patterns.()
: Groups patterns and captures matched text.Practical Use Cases
The re
module in Python offers a comprehensive set of tools for regular expression-based text processing. By utilizing functions like re.match()
, re.search()
, re.findall()
, re.sub()
, and re.split()
, you can efficiently handle complex string manipulation tasks. Mastering the re
module enhances your ability to validate, extract, and transform text data effectively in your Python programs.