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