Check if a string is suffix of another in Python

In Python, checking if one string is a suffix of another is a common string manipulation task. A suffix is a substring that appears at the end of a string. For example, "ate" is a suffix of "unfortunate".

Python provides multiple approaches to solve this problem efficiently ?

Method 1: Using endswith() Method

The simplest approach is to use Python's built-in endswith() method ?

s = "ate"
t = "unfortunate"

result = t.endswith(s)
print(f"Is '{s}' a suffix of '{t}'? {result}")

Is 'ate' a suffix of 'unfortunate'? True

Method 2: Using String Slicing

Compare the last characters of the longer string with the shorter string ?

def is_suffix_slice(s, t):
    if len(s) > len(t):
        return False
    return t[-len(s):] == s

s = "ate"
t = "unfortunate"
result = is_suffix_slice(s, t)
print(f"Is '{s}' a suffix of '{t}'? {result}")

# Test with non-suffix
s2 = "fun"
result2 = is_suffix_slice(s2, t)
print(f"Is '{s2}' a suffix of '{t}'? {result2}")

Is 'ate' a suffix of 'unfortunate'? True
Is 'fun' a suffix of 'unfortunate'? False

Method 3: Character-by-Character Comparison

Manually compare characters from the end of both strings ?

def is_suffix_manual(s, t):
    s_len = len(s)
    t_len = len(t)
    
    if s_len > t_len:
        return False
    
    for i in range(s_len):
        if s[s_len - i - 1] != t[t_len - i - 1]:
            return False
    
    return True

s = "ate"
t = "unfortunate"
result = is_suffix_manual(s, t)
print(f"Is '{s}' a suffix of '{t}'? {result}")

# Additional test cases
test_cases = [
    ("ing", "programming", True),
    ("xyz", "hello", False),
    ("hello", "hi", False)
]

for suffix, string, expected in test_cases:
    result = is_suffix_manual(suffix, string)
    print(f"'{suffix}' suffix of '{string}': {result}")

Is 'ate' a suffix of 'unfortunate'? True
'ing' suffix of 'programming': True
'xyz' suffix of 'hello': False
'hello' suffix of 'hi': False

Comparison

Conclusion

Use endswith() for most suffix checking tasks as it's the most readable and Pythonic approach. String slicing offers a simple alternative, while manual comparison helps understand the underlying logic.