Python | re.search() vs re.match()

Prerequisite: Regex in Python

The re.search() and re.match() both are functions of re module in python. These functions are very efficient and fast for searching in strings. The function searches for some substring in a string and returns a match object if found, else it returns none.

There is a difference between the use of both functions. Both return the first match of a substring found in the string, but re.match() searches only from the beginning of the string and return match object if found. But if a match of substring is found somewhere in the middle of the string, it returns none. 
While re.search() searches for the whole string even if the string contains multi-lines and tries to find a match of the substring in all the lines of string.

Example :

Python3

# import re module
import re

Substring ='string'


String1 ='''We are learning regex with geeksforgeeks
         regex is very useful for string matching.
          It is fast too.'''
String2 ='''string We are learning regex with geeksforgeeks
         regex is very useful for string matching.
          It is fast too.'''

# Use of re.search() Method
print(re.search(Substring, String1, re.IGNORECASE))
# Use of re.match() Method
print(re.match(Substring, String1, re.IGNORECASE))

# Use of re.search() Method
print(re.search(Substring, String2, re.IGNORECASE))
# Use of re.match() Method
print(re.match(Substring, String2, re.IGNORECASE))

Output :

<re.Match object; span=(75, 81), match='string'>
None
<re.Match object; span=(0, 6), match='string'>
<re.Match object; span=(0, 6), match='string'>

Conclusion :

1. re.search() is returning match object and implies that first match found at index 69.
2. re.match() is returning none because match exists in the second line of the string and re.match() only works if the match is found at the beginning of the string. 
3. re.IGNORECASE is used to ignore the case sensitivity in the strings. 
4. Both re.search() and re.match() returns only the first occurrence of a substring in the string and ignore others.