CODEWITHSUNDEEP
python
ApocalypticNut
ApocalypticNut

Reputation: 135

Python permutations

I am trying to generate pandigital numbers using the itertools.permutations function, but whenever I do it generates them as a list of separate digits, which is not what I want.

For example:

for x in itertools.permutations("1234"):
    print(x)

will produce:

('1', '2', '3', '4')
('1', '2', '4', '3')
('1', '3', '2', '4')
('1', '3', '4', '2')
('1', '4', '2', '3')
('1', '4', '3', '2'), etc.

whereas I want it to return 1234, 1243, 1324, 1342, 1423, 1432, etc. How would I go about doing this in an optimal fashion?

Upvotes: 2

Views: 754

Answers (3)

Kobi K
Kobi K

Reputation: 7931

itertools.permutations takes an iterable and returns an iterator yielding tuples.

Use join() that return a string which is the concatenation of the strings in the iterable iterable

join() DOCS, itertools.permutations DOCS

Use this:

import itertools

for x in itertools.permutations("1234"):
    print (''.join(x))

Output:

1234
1243
1324
1342
1423
1432
2134
2143
2314
2341
....

Upvotes: 3

Deelaka
Deelaka

Reputation: 13693

A list comprehension with the built-in str.join() function is what you need:

import itertools
a = [''.join(i) for i in itertools.permutations("1234") ]
print(a)

Output:

['1234', '1243', '1324', '1342', '1423', '1432', '2134', '2143', '2314', '2341', '2413', '2431', '3124', '3142', '3214', '3241', '3412', '3421', '4123', '4132', '4213', '4231', '4312', '4321']

Upvotes: 5

Vahid Kharazi
Vahid Kharazi

Reputation: 6033

see itertools.permutations return tuple. see join function:

In [1]: ''.join(('1','2','3'))
Out[1]: '123'

try this:

for x in itertools.permutations("1234"):
        print ''.join(x)

Upvotes: 2

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