# Count the Number of matching characters in a pair of string in Python

PythonServer Side ProgrammingProgramming

We are given two strings. We need to find the count it of the characters in the first string which are also present in a second string.

## With set

The set function gives us unique values all the elements in a string. We also use the the & operator which finds the common elements between the two given strings.

## Example

Live Demo

strA = 'Tutorials Point'
uniq_strA = set(strA)
# Given String
print("Given String\n",strA)
strB = 'aeio'
uniq_strB = set(strB)
# Given String
print("Search character strings\n",strB)
common_chars = uniq_strA & uniq_strB
print("Count of matching characters are : ",len(common_chars))

## Output

Running the above code gives us the following result −

Given String
Tutorials Point
Search character strings
aeio
Count of matching characters are : 3

## With re.search

We use the search function from the re module. We use a count variable and keep incrementing it when the search result is true.

## Example

Live Demo

import re
strA = 'Tutorials Point'
# Given String
print("Given String\n",strA)
strB = 'aeio'
# Given String
print("Search character strings\n",strB)
cnt = 0
for i in strA:
if re.search(i, strB):
cnt = cnt + 1
print("Count of matching characters are : ",cnt)

## Output

Running the above code gives us the following result −

Given String
Tutorials Point
Search character strings
aeio
Count of matching characters are : 5