Hackerrank Mutations problem solution in Python | python problem solution

August 9, 2022January 14, 2023 blogTech

Table of Contents

We have seen that lists are mutable (they can be changed), and tuples are immutable (they cannot be changed).

Let’s try to understand this with an example.

You are given an immutable string, and you want to make changes to it.

Example

>>> string = "abracadabra"

You can access an index by:

>>> print string[5]
a

What if you would like to assign a value?

>>> string[5] = 'k' 
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
TypeError: 'str' object does not support item assignment

How would you approach this?

One solution is to convert the string to a list and then change the value.

Example

>>> string = "abracadabra"
>>> l = list(string)
>>> l[5] = 'k'
>>> string = ''.join(l)
>>> print string
abrackdabra

Another approach is to slice the string and join it back.

Example

>>> string = string[:5] + "k" + string[6:]
>>> print string
abrackdabra

Task
Read a given string, change the character at a given index and then print the modified string.
Function Description

Complete the mutate_string function in the editor below.

mutate_string has the following parameters:

string string: the string to change
int position: the index to insert the character at
string character: the character to insert

Returns

string: the altered string

Input Format

The first line contains a string, .
The next line contains an integer , the index location and a string , separated by a space.

Sample Input

STDIN           Function
-----           --------
abracadabra     s = 'abracadabra'
5 k             position = 5, character = 'k'

Sample Output

abrackdabra

Problem solution in Python 2 programming.

S=raw_input()
i,c=map(str,raw_input().split())
i=int(i)
print S[:i] + c + S[i+1:]

Problem solution in Python 3 programming.

string = input()
line = input().split()
i, c = int(line[0]), line[1]
print(string[:i] + c + string[i+1:])

Problem solution in PyPy programming.

# Enter your code here. Read input from STDIN. Print output to STDOUT
S=raw_input()
n,a=raw_input().split()
l=list(S)
l[int(n)]=a
print ''.join(l)

Problem solution in PyPy3 programming.

def mutate_string(string, position, character)
print(input())
string=list(input())
[a,b]=(input().split())
print ([a,b])
print(string[int(a)])
print(i)
print(rep)
string = string[:i] + str(b) + string[(i+1):]
string[int(a)]= str(b)
string="".join(string)
print (string)

return

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