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Python Math: Print all permutations of a given string

Python Math: Exercise-16 with Solution

Write a Python program to print all permutations of a given string (including duplicates).

In mathematics, the notion of permutation relates to the act of arranging all the members of a set into some sequence or order, or if the set is already ordered, rearranging (reordering) its elements, a process called permuting. These differ from combinations, which are selections of some members of a set where order is disregarded.

In the following image each of the six rows is a different permutation of three distinct balls

permutation of numbers

Sample Solution:-

Python Code:

def permute_string(str):
    if len(str) == 0:
        return ['']
    prev_list = permute_string(str[1:len(str)])
    next_list = []
    for i in range(0,len(prev_list)):
        for j in range(0,len(str)):
            new_str = prev_list[i][0:j]+str[0]+prev_list[i][j:len(str)-1]
            if new_str not in next_list:
                next_list.append(new_str)
    return next_list

print(permute_string('ABCD'));

Sample Output:

['ABCD', 'BACD', 'BCAD', 'BCDA', 'ACBD', 'CABD', 'CBAD', 'CBDA', 'ACDB', 'CADB', 'CDAB', 'CDBA', 'ABDC', 'BADC
', 'BDAC', 'BDCA', 'ADBC', 'DABC', 'DBAC', 'DBCA', 'ADCB', 'DACB', 'DCAB', 'DCBA'] 

Flowchart:

Flowchart: Print all permutations of a given string

Visualize Python code execution:

The following tool visualize what the computer is doing step-by-step as it executes the said program:

Python Code Editor:

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