Python : How to remove characters from a string by Index ?

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Ways to remove i’th character from string in Python

Here we are going to discuss how to remove characters from a string in a given range of indices or at specific index position.

So we will discuss different different methods for this.

Naive Method

In this method, we have to first run the loop and append the characters .After that  build a new string from the existing one .

test_str = "WelcomeBtechGeeks"
  
# Printing original string 
print ("The original string is : " + test_str)
  
# Removing char at pos 3
# using loop
new_str = ""
  
for i in range(len(test_str)):
    if i != 2:
        new_str = new_str + test_str[i]
  
# Printing string after removal  
print ("The string after removal of i'th character : " + new_str)

Output:

RESTART: C:/Users/HP/Desktop/article3.py
The original string is : WelcomeBtechGeeks
The string after removal of i'th character : WecomeBtechGeeks

So in above eoutput you have seen that we have remove character of position three that is ‘l’.

This method is very slow if we compare with other methods.

Using str.replace()

str.replace() can replace the particular index with empty char, and hence solve the issue.

test_str = "WelcomeBtechGeeks"
  
# Printing original string 
print ("The original string is : " + test_str)
  
# Removing char at pos 3
# using replace
new_str = test_str.replace('e', '1')
  
# Printing string after removal  
# removes all occurrences of 'e'
print ("The string after removal of i'th character( doesn't work) : " + new_str)
  
# Removing 1st occurrence of e, i.e 2nd pos.
# if we wish to remove it.
new_str = test_str.replace('e', '', 1)
  
# Printing string after removal  
# removes first occurrences of e
print ("The string after removal of i'th character(works) : " + new_str)

Output:

RESTART: C:/Users/HP/Desktop/article3.py
The original string is : WelcomeBtechGeeks
The string after removal of i'th character( doesn't work) : W1lcom1Bt1chG11ks
The string after removal of i'th character(works) : WlcomeBtechGeeks

So in above output you can see that first we have replace all ‘e’ present in original word.After that we replace only first occurrence of e.This method is also not very useful but sometime we are using this.

Using slice + concatenation

In this method we will use string slicing.Then using string concatenation of both, i’th character can appear to be deleted from the string.

test_str = "WelcomeBtechGeeks"
  
# Printing original string 
print ("The original string is : " + test_str)
  
#Removing char at pos 3
# using slice + concatenation
new_str = test_str[:2] +  test_str[3:]
  
# Printing string after removal  
# removes ele. at 3rd index
print ("The string after removal of i'th character : " + new_str)

Output:

RESTART: C:/Users/HP/Desktop/article3.py
The original string is : WelcomeBtechGeeks
The string after removal of i'th character : WecomeBtechGeeks

Using str.join() and list comprehension

In this method each string is converted in list then each of them is joined to make a string.

test_str = "WelcomeBtechGeeks"
  
# Printing original string 
print ("The original string is : " + test_str)
  
# Removing char at pos 3
# using join() + list comprehension
new_str = ''.join([test_str[i] for i in range(len(test_str)) if i != 2])
  
# Printing string after removal  
# removes ele. at 3rd index
print ("The string after removal of i'th character : " + new_str)

Output:

RESTART: C:/Users/HP/Desktop/article3.py
The original string is : WelcomeBtechGeeks
The string after removal of i'th character : WecomeBtechGeeks

Conclusion:

So in this article we have seen different method to remove characters from a string in a given range of indices or at specific index position.Enjoy learning guys.