Merging two strings with Suffix and Prefix using Python

String manipulation often requires merging two strings based on shared suffix and prefix sequences. This article demonstrates how to merge two strings with overlapping parts using Python, avoiding redundant duplication while preserving all characters from both original strings.

Understanding String Merging with Overlaps

When merging strings, we need to identify if the suffix of the first string matches the prefix of the second string. For example, if we have "hello world" and "world peace", the word "world" appears at the end of the first string and the beginning of the second string. Smart merging would combine them as "hello world peace" instead of "hello world world peace".

Method 1: Using Overlap Detection

This approach finds the longest overlapping sequence between the suffix of the first string and the prefix of the second string ?

def merge_strings(st1, st2):
    # Find maximum possible overlap length
    min_overlap_len = min(len(st1), len(st2))
    
    # Check for overlaps from longest to shortest
    for i in range(min_overlap_len, -1, -1):
        if st1.endswith(st2[:i]):
            return st1 + st2[i:]
    
    # If no overlap found, concatenate normally
    return st1 + st2

# Example
str1 = 'hello world'
str2 = 'world peace'
result = merge_strings(str1, str2)
print(f"'{str1}' + '{str2}' = '{result}'")

The output shows the merged string without duplication ?

'hello world' + 'world peace' = 'hello world peace'

How It Works

The function iterates through possible overlap lengths, checking if the suffix of the first string matches the prefix of the second string. When a match is found, it merges the strings by appending only the nonoverlapping part of the second string.

Method 2: Simple String Concatenation

For cases where you want to merge strings without overlap detection, simple concatenation works ?

def simple_merge(prefix, suffix):
    return prefix + suffix

# Example
prefix = "Hello, "
suffix = "world!"
result = simple_merge(prefix, suffix)
print(f"'{prefix}' + '{suffix}' = '{result}'")

# Another example with space handling
prefix2 = "Python"
suffix2 = " programming"
result2 = simple_merge(prefix2, suffix2)
print(f"'{prefix2}' + '{suffix2}' = '{result2}'")

The output demonstrates basic string concatenation ?

'Hello, ' + 'world!' = 'Hello, world!'
'Python' + ' programming' = 'Python programming'

Advanced Example with Multiple Overlaps

Here's an example testing different overlap scenarios ?

def test_merging():
    test_cases = [
        ("hello world", "world peace"),
        ("Python prog", "programming"),
        ("data", "science"),
        ("overlap", "laptop"),
    ]
    
    for str1, str2 in test_cases:
        merged = merge_strings(str1, str2)
        print(f"'{str1}' + '{str2}' = '{merged}'")

def merge_strings(st1, st2):
    min_overlap_len = min(len(st1), len(st2))
    for i in range(min_overlap_len, -1, -1):
        if st1.endswith(st2[:i]):
            return st1 + st2[i:]
    return st1 + st2

test_merging()

'hello world' + 'world peace' = 'hello world peace'
'Python prog' + 'programming' = 'Python programming'
'data' + 'science' = 'datascience'
'overlap' + 'laptop' = 'overlaptop'

Comparison

Conclusion

Use overlap detection when merging strings that might have common suffixprefix patterns. For simple concatenation without overlap concerns, basic string concatenation is sufficient and more efficient.