Python - Test if Substring occurs in specific position

Python – Test if Substring occurs in specific position

Last Updated : 01 Mar, 2020

Sometimes, while working with python strings, we can have a problem in which we need to test occurrence of substring. There is straight forward way to test this. But sometimes, we have a more specific problem in which we need to test if substring occurs at that particular position. Let’s discuss certain ways in which this task can be performed.

Method #1 : Using loop
This is brute method to solve this problem. In this we iterate the string and when index occur we test for substring characters simultaneously.

# Python3 code to demonstrate working of 
# Test if Substring occurs in specific position
# Using loop
  
# initializing string 
test_str = "Gfg is best"
  
# printing original string 
print("The original string is : " + test_str)
  
# initializing range 
i, j = 7, 11
  
# initializing substr
substr = "best"
  
# Test if Substring occurs in specific position
# Using loop
res = True
k = 0
for idx in range(len(test_str)):
    if idx >= i  and idx < j:
        if test_str[idx] != substr[k]:
            res = False
            break
        k = k + 1
          
# printing result 
print("Does string contain substring at required position ? : " + str(res)) 

Output :

The original string is : Gfg is best
Does string contain substring at required position ? : True

Method #2 : Using string slicing
This is one-liner way to perform this task. In this, we check the substring in string using string slicing.

# Python3 code to demonstrate working of 
# Test if Substring occurs in specific position
# Using string slicing 
  
# initializing string 
test_str = "Gfg is best"
  
# printing original string 
print("The original string is : " + test_str)
  
# initializing range 
i, j = 7, 11
  
# initializing substr
substr = "best"
  
# Test if Substring occurs in specific position
# Using string slicing
res = test_str[i : j]  == substr
          
# printing result 
print("Does string contain substring at required position ? : " + str(res)) 

Output :

The original string is : Gfg is best
Does string contain substring at required position ? : True

Attention geek! Strengthen your foundations with the Python Programming Foundation Course and learn the basics.

To begin with, your interview preparations Enhance your Data Structures concepts with the Python DS Course. And to begin with your Machine Learning Journey, join the Machine Learning – Basic Level Course

My Personal Notes

Related Articles