How to Remove Letters From a String in Python

Strings are data types used to represent text/characters. In this article, we present different methods for the problem of removing the i_th character from a string and talk about possible solutions that can be employed in achieving them using Python.

Input: 'Geeks123For123Geeks'
Output: GeeksForGeeks
Explanation: In This, we have removed the '123' character from a string.

Remove Characters From a String in Python

These are the following methods using which we can remove letters from a string in Python:

• Using str.replace()
• Using translate()
• Using recursion
• Using Native Method
• Using slice + concatenation
• Using str.join()
• Using bytearray
• Using removeprefix()

Remove Characters From a String Using replace()

str.replace() can be used to replace all the occurrences of the desired character. It can also be used to perform the task of character removal from a string as we can replace the particular index with empty char, and hence solve the issue. 

The string after removal of i'th character( doesn't work) : GksForGks
The string after removal of i'th character(works) : GeekForGeeks

Time Complexity: O(n)
Space Complexity: O(n)

Drawback: The major drawback of using replace() is that it fails in cases where there are duplicates in a string that match the char at pos. i. replace() replaces all the occurrences of a particular character and hence would replace all the occurrences of all the characters at pos i. We can still sometimes use this function if the replacing character occurs for 1^st time in the string.

Remove the Specific Character from the String using Translate()

This method provides a strong mechanism to remove characters from a string. In this method, we removed 123 from GeeksforGeeks using string.translate(). 

Output

GeeksForGeeks

Time Complexity: O(n)
Space Complexity: O(m)

Remove the Specific Character from the String Using Recursion

To remove the ith character from a string using recursion, you can define a recursive function that takes in the string and the index to be removed as arguments. The function will check if the index is equal to 0, in this case it returns the string with the first character removed. If the index is not 0, the function can return the first character of the string concatenated with the result of calling the function again on the string with the index decremented by 1.

Output

The string after removal of ith character: GeksForGeeks

Time Complexity: O(n)
Space Complexity: O(n)

Remove Letters From a String Using the Native Method

In this method, one just has to run a Python loop and append the characters as they come, and build a new string from the existing one except when the index is i. 

The string after removal of i'th character : GeksForGeeks

Time Complexity: O(n)
Space Complexity: O(n), where n is length of string.

Remove the i_th Character from the String Using Slice

One can use string slice and slice the string before the pos i, and slice after the pos i. Then using string concatenation of both, i_th character can appear to be deleted from the string. 

The string after removal of i'th character : GeksForGeeks

Time Complexity: O(n)
Space Complexity: O(n)

Remove the i_th Character from the String Using str.join()

In this method, each element of a string is first converted as each element of the list, and then each of them is joined to form a string except the specified index. 

The string after removal of i'th character : GeksForGeeks

Time Complexity: O(n)
Space Complexity: O(n)

Delete Letters From a String in Python Using bytearray

Define the function remove_char(s, i) that takes a string s and an integer i as input. And then Convert the input string s to a bytearray using bytearray(s, ‘utf-8’). Delete the i’th element from the bytearray using del b[i]. Convert the modified bytearray back to a string using b.decode() and Return the modified string.

Output

hell world

Time Complexity: O(n)
Space Complexity: O(n)

Remove Letters From a String Using removeprefix()

removeprefix() removes the prefix and returns the rest of the string. We can remove letters from a string for any specific index by dividing the string into two halves such that the letter that we wanted to remove comes in the prefix of any of the two partition and then we can apply the method to remove the letter.

Output:

eeksforGeeks
GeeksorGeeks

Time Complexity: O(n)
Space Complexity: O(n)

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