How do I create a list of lists?

Question

I want to be able to enter a list of names and then for each name on that list I want to create a list of predictions on who each person thinks will win a match.

For example, I would have names = [bob, bill, fred]

Then for each name in that list I'd like to have the user enter who they think will win. So in this example I would end up with

bobs_predictions = []
bills_predictions = []
freds_predictions = []

Hopefully you understand what I mean. Basically I'd like to create a list of lists where python names the list based on a list of names...

You want a dictionary (or mapping, same thing). – Reut Sharabani Jul 22 '16 at 12:42 — Reut Sharabani, Jul 22 '16 at 12:42
thanks Reut, this worked perfectly – Luke Bray Jul 22 '16 at 18:24 — Luke Bray, Jul 22 '16 at 18:24

Reut Sharabani · Answer 1 · 2016-07-22T12:57:14.357

3

You want to use a mapping:

predictions = {
    "bob": [...],
    "bill": [...],
    "fred": [...]
}

To instantiate (with empty predictions) from a list of names:

predictions = {name: [] for name in names}

To get bob's predictions:

bobs_predictions = predictions['bob']

To add a prediction to bob:

bobs_predictions.append(prediction)

edited Jul 22 '16 at 12:57

answered Jul 22 '16 at 12:43

Reut Sharabani

30,449
6
70
88

@MosesKoledoye [no, you don't](http://stackoverflow.com/questions/15516413/dict-fromkeys-all-point-to-same-list). – Łukasz Rogalski Jul 22 '16 at 12:47
@ŁukaszRogalski Oh sprite! Didn't think of that. Good one – Moses Koledoye Jul 22 '16 at 13:05

How do I create a list of lists?

1 Answers1