Python re.finditer() method

---

---

The Python re.finditer() method returns an iterator yielding match objects for all non-overlapping matches of a pattern in a string.

The method re.findall() which returns a list of matched strings whereas the method re.finditer() provides more detailed information about each match such as the start and end positions within the string. Each match object can be used to extract matched substrings and their positions.

This method is particularly useful when we need to process or analyze each match in detail.

Syntax

Following is the syntax and parameters of Python re.finditer() method −

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

Parameters

Following are the parameters of the python re.finditer() method −

• pattern: The regular expression pattern to search for.
• string: The string to search within.
• maxsplit(optional): The maximum number of splits. Default value is 0 which means "no limit".
• flags(optional): Flags to modify the matching behavior (e.g., re.IGNORECASE)

Return value

This method returns an iterator of match objects

Example 1

Following is the basic example of the re.finditer() method. This example finds all numeric sequences in the string and prints each match −

import re

matches = re.finditer(r'\d+', 'There are 123 apples and 456 oranges.')
for match in matches:
    print(match.group())  

Output

123
456

Example 2

This example finds all words in the string and prints each word with the help of the method re.finditer() −

import re

matches = re.finditer(r'\b\w+\b', 'Hello, world! Welcome to Python.')
for match in matches:
    print(match.group())  

Output

Hello
world
Welcome
to
Python

Example 3

In this example we use the re.IGNORECASE flag to perform a case-insensitive search and prints each match −

import re

matches = re.finditer(r'hello', 'Hello HELLO hello', re.IGNORECASE)
for match in matches:
    print(match.group())    

Output

Hello
HELLO
hello

Example 4

Here in this example we retrieve the start and end positions of each match in the string −

import re

matches = re.finditer(r'\d+', 'There are 123 apples and 456 oranges.')
for match in matches:
    print(match.group(), match.start(), match.end())  

Output

123 10 13
456 25 28