Python program to delete prefix substring from the given string

In this article, we will learn how to create a Python program to delete prefix substrings from a given string. A prefix is a group of characters that are added to the beginning of a string. When working with text data, you often need to remove common prefixes to clean or process the data efficiently.

For example, if the given string is "My shirt color is Red" and we want to delete the prefix "My", the final output becomes " shirt color is Red".

Methods for Removing Prefixes

Method 1: Using startswith() and Slicing

The startswith() method checks if a string starts with a given prefix and returns True or False. Combined with string slicing, we can remove the prefix ?

text = "Red pen"
prefix = "Red"

if text.startswith(prefix):
    result = text[len(prefix):]
    print("After deleting the prefix:", result)
else:
    print("Prefix not found")

After deleting the prefix:  pen

Method 2: Using lstrip()

The lstrip() method removes specified characters from the beginning of a string. However, it removes individual characters, not the exact substring ?

text = "The sky is blue in color"
prefix_chars = "The"
result = text.lstrip(prefix_chars)
print("After using lstrip():", result)

After using lstrip():  sky is blue in color

Method 3: Using removeprefix() (Python 3.9+)

Python 3.9 introduced the removeprefix() method, which removes the exact prefix substring if it exists ?

text = 'qwertyuiop'
result = text.removeprefix('qwe')
print("After removing prefix:", result)

After removing prefix: rtyuiop

Method 4: Custom Function

You can create a custom function to handle prefix removal for older Python versions ?

def remove_prefix(original_string, prefix):
    if original_string.startswith(prefix):
        return original_string[len(prefix):]
    else:
        return original_string

text = 'abcdefghijklmnopqrstuvwxyz'
result = remove_prefix(text, 'abcdefghijkl')
print('Original string:', text)
print('After removing prefix:', result)

Original string: abcdefghijklmnopqrstuvwxyz
After removing prefix: mnopqrstuvwxyz

Comparison of Methods

Conclusion

Use removeprefix() for Python 3.9+ as it's the most straightforward method. For older versions, combine startswith() with slicing or create a custom function. Avoid lstrip() when you need to remove exact prefixes rather than individual characters.