CODEWITHSUNDEEP
pythonpython-2.7iterator
JD3
JD3

Reputation: 410

How to generate all possible strings in python?

My goal is to be able to generate all possible strings (Letters and numbers) of length x and be able to activate a block of code for each one. (like an iterator) The only problem is the ones in the itertools don't make copies of the letter in the same string. For example:

I get "ABC" "BAC" "CAB" etc. instead of "AAA".

Any suggestions?

Upvotes: 11

Views: 23885

Answers (2)

Martijn Pieters
Martijn Pieters

Reputation: 1121924

Use itertools.product() if you want letters to repeat:

>>> from itertools import product
>>> from string import ascii_uppercase
>>> for combo in product(ascii_uppercase, repeat=3):
...     print ''.join(combo)
...
AAA
AAB
...
ZZY
ZZZ

itertools.combinations() and itertools.permutations() are not the correct tools for your job.

Upvotes: 12

ThiefMaster
ThiefMaster

Reputation: 318508

Use itertools.product():

>>> import itertools
>>> map(''.join, itertools.product('ABC', repeat=3))
['AAA', 'AAB', 'AAC', 'ABA', 'ABB', 'ABC', 'ACA', 'ACB', 'ACC', 'BAA', 'BAB', 'BAC', 'BBA', 'BBB', 'BBC', 'BCA', 'BCB', 'BCC', 'CAA', 'CAB', 'CAC', 'CBA', 'CBB', 'CBC', 'CCA', 'CCB', 'CCC']

Note that creating a list containing all combinations is very inefficient for longer strings - iterate over them instead:

for string in itertools.imap(''.join, itertools.product('ABC', repeat=3)):
    print string

To get all characters and numbers use string.uppercase + string.lowercase + string.digits.

Upvotes: 30

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