How to generate a random ID that is not already in a list in Python?

Question

I am trying to make a list of cues for a movie playback system.

Every time a cue is created I want to add an id to the cue object.

(Which looks something like)

{
    "name": "Cue One",
    "length": 5000,
    "id": xxx
}

Each cue object will get stored in a list of cues. However, I want to know the best way to generate ids for each cue since they will ultimately be looked up, in the list, by ID.

I know I could do something like (max[cue.id for cues in cuelist] + 1) or I could use the random module and check to see if the randint is not in the cues id, however I do not know what the most "legit" way to do this is.

Is there some specific technique or algorithm for this sort of problem?

Why not use [uuid](https://docs.python.org/3/library/uuid.html) to generate your ids? — idjaw, Mar 07 '16 at 20:52
Why not store the cues in a `list`. The `id` field becomes redundant when you can look them up by index. — quamrana, Mar 07 '16 at 20:55

score 3 · Accepted Answer · answered Mar 07 '16 at 20:53

3

I think what you are looking for are UUIDs Refering to python documentation: https://docs.python.org/2/library/uuid.html

answered Mar 07 '16 at 20:53

drgn

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Just a small addition: UUID are not guaranteed to be unique, but that chance that they aren't is negligible. – Georg Schölly Mar 07 '16 at 21:02
@GeorgSchölly how negligible? – Startec Mar 08 '16 at 03:32
@Startec: [don't worry about it negligible](http://stackoverflow.com/questions/1155008/how-unique-is-uuid), unless you combine UUID version 4 with a bad RNG. – Georg Schölly Mar 08 '16 at 12:39

How to generate a random ID that is not already in a list in Python?

1 Answers1