Converting nested for-loops into a recursive function in Python

Question

I was trying to create a code to display all possible permutations of a string without using itertools, so I came up with a basic idea of how I could get this to work using these ugly nested for-loops but now I want to convert this into a function for any string with length 'n', I'm kinda new to recursion so I need some help sorting this out.

wrdinp=input("Enter a word: ")
d=[]
#Works for string with length 4
for a in wrdinp:
    for b in wrdinp:
        if b!=a:
            for c in wrdinp:
                if c!=a and c!=b:
                    for d in wrdinp:
                        if d!=a and d!=b and d!=c:
                            d.append(a+b+c+d)
print("Permutations:",d)

I need a function that takes in a string of any length and returns a list that contains the various permutations of the string.

You can find a solution via Google without much difficulty: geeksforgeeks.org/…. You only need to convert the string to a list to apply the algorithm. — GZ0
– GZ0, Commented Aug 10, 2019 at 12:21

Mahir Islam · Accepted Answer · 2019-08-10 12:15:29Z

3

This is a way to do it in recursion:

def permutations(wrdinp):
    if len(wrdinp) <= 1:
       return [wrdinp]
    else:
       d = []
       for e in permutations(wrdinp[:-1]):
           for i in range(len(e)+1):
               d.append(e[:i] + wrdinp[-1] + e[i:])
       return d
wrdinp=input("Enter a word: ")
result = permutations(wrdinp)
print(result)

Hope it helps :)

answered Aug 10, 2019 at 12:15

Mahir Islam

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2 Comments

Praneet R Over a year ago

Thank you so much, it helped! My first day here on Stack Overflow, already loving it due to people like you ready to help others :)

Mahir Islam Over a year ago

@PraneetR really happy it helped you. You can also repay it back by checking this answer as the best one when it is available, which should be available after a while. Hope you keep the request :)

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