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Generate all permutations of a list

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Wed. Oct. 11th, 2006 2:41 PM

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nil_ptr

permutations | permute | python

1 comments

This is snippet of code solves the interesting (and specialized) problem of generating all permutations of a list. I hope you like recursion.

For exmaple:

permute( [0,1,2] )

would return

[[0,1,2],[0,2,1],[1,0,2],[1,2,0],[2,0,1],[2,1,0]]

def permute( values, perms = list(), cur_perm = list() ):

    if len( values ) == 0:

        perms.append( cur_perm )

    else:

        for value in values:

            new_values = values[:]

            new_values.remove( value )

            new_perm = cur_perm[:]

            new_perm.append( value )

            permute( new_values, cur_perm = new_perm )

    return perms