Given a String, the task is to write a Python program to remove the nth index character from a non-empty string
Examples:
Input: str = "Stable" Output: Modified string after removing 4 th character Stabe Input: str = "Arrow" Output: Modified string after removing 4 th character Arro
The first approach uses a new string variable for storing the modified string. We keep a track of the characters of the string and as soon as we encounter a character at nth index, we don’t copy it to the modified string variable. Else, we copy it to a new variable.
Python3
# declaring a string variablestr = "GeeksforLazyroar is fun."# index to remove character atn = 4# declaring an empty string variable for storing modified stringmodified_str = ''# iterating over the stringfor char in range(0, len(str)): # checking if the char index is equivalent to n if(char != n): # append original string character modified_str += str[char]print("Modified string after removing ", n, "th character ")print(modified_str) |
Output:
Modified string after removing 4 th character GeekforLazyroar is fun.
Time Complexity = O(n), where n is the length of the string.
Auxiliary Space: O(n)
The second approach uses the idea of extraction of a sequence of characters within a range of index values. The syntax used in Python is as follows :
string_name[start_index : end_index]
– extracts the characters starting at start_index
and less than end_index, that is, up to end_index-1.
If we don’t specify the end_index, it computes till the length of the string.
Therefore, we extract all the characters of a string in two parts, first until nth index and the other beginning with n+1th index. We then append these two parts together.
Python3
# declaring a string variablestr = "GeeksforLazyroar is fun."# index to remove character atn = 8# extracts 0 to n-1th indexfirst_part = str[0:n]# extracts characters from n+1th index until the endsecond_part = str[n+1:]print("Modified string after removing ", n, "th character ")# combining both the parts togetherprint(first_part+second_part) |
Output:
Modified string after removing 8 th character Geeksforeeks is fun.
Time Complexity = O(n), where n is the length of the string.
Auxiliary Space = O(n)
Third Approach :
Python3
#Python program to remove nth index character from non-empty string# declaring a string variablestr = "GeeksforLazyroar is fun."# index to remove character atn = 8print("Modified string after removing ", n, "th character ")str=str.replace(str[n],"",1)print(str) |
Modified string after removing 8 th character Geeksforeeks is fun.
Fourth Approach: Type casting into list and del to remove character
Python3
#input stringstr1 = "GeeksforLazyroar is fun."# index to remove character atn=4#type castingstr1=list(str1)print("Modified string after removing ", n, "th character ")del str1[n]#printing as listprint(''.join(str1)) |
Modified string after removing 4 th character GeekforLazyroar is fun.
Time Complexity = O(n), where n is the length of the string.
Auxiliary Space = O(n)
Approach using islice
Step-by-step algorithm to remove the nth index character from a non-empty string using the islice approach:
Import the islice module from itertools.
Declare a non-empty string.
Declare an integer n that represents the index of the character to remove.
Use the islice function to extract all characters from the beginning of the string to the (n-1)th character, then join them using the join method and store the result.
Use the islice function again to extract all characters from the (n+1)th character to the end of the string, then join them using the join method.
Add the two strings from steps 4 and 5 together and store the result.
Print the modified string.
Python3
from itertools import islice#declaring a string variablestr = "GeeksforLazyroar is fun."#index to remove character atn = 8#using islice to extract characters from the stringresult = ''.join(islice(str, 0, n)) + ''.join(islice(str, n+1, len(str)))print("Modified string after removing ", n, "th character ", result) |
Modified string after removing 8 th character Geeksforeeks is fun.
Time complexity: O(n), where n is the length of the string. This is because the islice function must be called twice, and each call takes O(n) time in the worst case.
Auxiliary space complexity: O(n), where n is the length of the string. This is because we create two new strings, each with a length of up to n-1, and then join them together to create the modified string.
