Logic Building/Phase 3 - Level 4: String-based Recursion/Program

Replace Character Recursively

Replace all occurrences of a character recursively.

Logic BuildingAdvanced

Logic Building

def replace_char(s, old, new, index=0):
    # Base case
    if index >= len(s):
        return ""
    
    # Check current character
    if s[index] == old:
        char = new
    else:
        char = s[index]
    
    # Recurse
    return char + replace_char(s, old, new, index + 1)

# Test
text = input("Enter a string: ")
old_char = input("Enter character to replace: ")
new_char = input("Enter new character: ")
result = replace_char(text, old_char, new_char)
print(f"Result: {result}")

Output

Enter a string: Hello
Enter character to replace: l
Enter new character: x
Result: Hexlo

Replace character if matches, otherwise keep.

Key Concepts:

Base case: index >= len(s)
Check if current char matches
Replace or keep, then recurse

Remove Spaces Recursively

Remove Occurrences Recursively