Permuting Strings in Python

Finding all possible permutations of a given string can be a challenging task. However, Python provides a straightforward solution using the itertools module.

Solution: itertools.permutations()

The itertools.permutations() method is specifically designed for generating permutations. It takes an iterable as input and returns a generator object that iterates over all possible permutations of the iterable.

In the case of a string, we can convert it to an iterable using the list() function. To obtain all possible permutations of the string, we use the following code:

from itertools import permutations
string = 'stack'
perms = [''.join(p) for p in permutations(list(string))]

The result will be a list of strings containing all permutations of the original string.

Handling Duplicates

If you wish to exclude duplicate permutations, you can utilize a set as it only retains unique elements.

perms = set([''.join(p) for p in permutations(list(string))])

Advantages of itertools.permutations()

• Efficient: The method utilizes a C-based implementation for speedy execution.
• Comprehensive: It generates all possible permutations without repeating any.
• Customizable: The number of permutations can be controlled by specifying the 'r' parameter.

Example Output

For the string 'stack', the output list will contain the following permutations:

['stack', 'stakc', 'stcak', 'stcka', 'stkac', 'stkca', 'satck', 'satkc', 'sactk', 'sackt', 'saktc', 'sakct', 'sctak', 'sctka', 'scatk', 'scakt', 'sckta', 'sckat', 'sktac', 'sktca', 'skatc', 'skact', 'skcta', 'skcat', 'tsack', 'tsakc', 'tscak', 'tscka', 'tskac', 'tskca', 'tasck', 'taskc', 'tacsk', 'tacks', 'taksc', 'takcs', 'tcsak', 'tcska', 'tcask', 'tcaks', 'tcksa', 'tckas', 'tksac', 'tksca', 'tkasc', 'tkacs', 'tkcsa', 'tkcas', 'astck', 'astkc', 'asctk', 'asckt', 'asktc', 'askct', 'atsck', 'atskc', 'atcsk', 'atcks', 'atksc', 'atkcs', 'acstk', 'acskt', 'actsk', 'actks', 'ackst', 'ackts', 'akstc', 'aksct', 'aktsc', 'aktcs', 'akcst', 'akcts', 'cstak', 'cstka', 'csatk', 'csakt', 'cskta', 'cskat', 'ctsak', 'ctska', 'ctask', 'ctaks', 'ctksa', 'ctkas', 'castk', 'caskt', 'catsk', 'catks', 'cakst', 'cakts', 'cksta', 'cksat', 'cktsa', 'cktas', 'ckast', 'ckats', 'kstac', 'kstca', 'ksatc', 'ksact', 'kscta', 'kscat', 'ktsac', 'ktsca', 'ktasc', 'ktacs', 'ktcsa', 'ktcas', 'kastc', 'kasct', 'katsc', 'katcs', 'kacst', 'kacts', 'kcsta', 'kcsat', 'kctsa', 'kctas', 'kcast', 'kcats']