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Say you have a set of characters (ex. abcdef). I was wondering how I would go about generating all the possible srings I could make with these letters that are size X (ex. 7). I know this will result in a list that is number of characters in set C x in length but am not quite sure how to accomplish it. Any help would be greatly appreciated.

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OP wants all length‑X strings from a given character set and clarified that characters may not repeat. Note: with no repetition the requested length r must be <= number of distinct characters (so asking for length 7 from "abcdef" is impossible without repeats).

suggested combinations; that applies when order does not matter. For strings order matters, so use permutations (arrangements without repetition). The count is P(n,r) = n! / (n-r)!, which is useful to check feasibility before generating anything.

Here is a simple Python generator for permutations (no repeats):

from itertools import permutations

chars = 'abcdef'
r = 3

if r > len(set(chars)):
    raise ValueError('r cannot be larger than number of unique characters')

for p in permutations(chars, r):
    s = ''.join(p)
    print(s)

If repeats are allowed (each position can reuse any character), use Cartesian product instead:

from itertools import product

for p in product(chars, repeat=r):
    print(''.join(p))

Practical notes and pitfalls:

  • Duplicate characters in the input produce duplicate output permutations; remove duplicates from the input first if distinct letters are intended, or filter outputs with a seen set (memory tradeoff).
  • Counts grow very quickly. Compute P(n,r) first (use math.factorial) to avoid attempting to generate billions of strings.
  • For large result sets, stream results to a file or process them on the fly instead of building a list in memory.

This clarifies the permutations vs combinations distinction and gives direct, memory‑friendly Python patterns to generate the required strings.

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Member Avatar for Momerath

Can you repeat characters?

Member Avatar for tr6699

Each character can only be used once in the final string.

Member Avatar for Momerath

Then you want Combinations

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