Python - Test if Substring occurs in specific position

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

My Personal Notes

Python – Test if Substring occurs in specific position

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