Python Mutations HackerRank Solution
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, string .
The next line contains an integer position, the index location, and a string character separated by a space.
Sample Input 0
STDIN Function
----- --------
abracadabra s = 'abracadabra'
5 k position = 5, character = 'k'
Sample Output 0
abrackdabra
Solution:
def mutate_string(string, position, character):
lst = list(string)
lst[position] = character
string = "".join(lst)
return string
if __name__ == '__main__':
s = input()
i, c = input().split()
s_new = mutate_string(s, int(i), c)
print(s_new)
Steps Used in solving the problem -
Step 1: First we created an function. this function takes a string, a position, and a character as input.
Step 2: then we converted our string into a list.
Step 3: After this, we defined the specific position of our list as equal to a character.
Step 4: then we used a join method and joined our converted string.
Step 5: In the last step, we returned our string.
