Python: How to apply list comprehension to make list of lambdas?

Question

This code prints 2 2 2 instead of 1 2 3. I'd understand this result if k being referred to is shared between each list items, but I couldn't be certain about it.

flist = [(lambda x: k) for k in range(3)]
print(flist[0](0), flist[1](0), flist[2](0))
print(k)  # Fails as expected

How does list comprehension work exactly? On what namespace does k exist?
How should I change the code to get 1 2 3 with about the same code complexities/length as list comprehension? I'm hardcoding list of flists, and I don't want my code to be excessively long.

flist = [(lambda x, y=k: y) for k in range(3)] – Marcin Nov 26 '14 at 05:27 — Marcin, Nov 26 '14 at 05:27

score 0 · Answer 1 · answered Nov 26 '14 at 05:23

0

this is simple it should be like this:

>>> flist = [ k+1 for k in range(3)]
>>> flist
[1, 2, 3]

answered Nov 26 '14 at 05:23

Hackaholic

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I'm making array of functions, not its individual results. – whyask37 Nov 26 '14 at 05:23
can you show the expected output what you want – Hackaholic Nov 26 '14 at 05:24
[lambda x:0, lambda x:1, lambda x:2] Silly mistakes; – whyask37 Nov 26 '14 at 05:24
lambda is inbuilt function, it will be stored as function not string – Hackaholic Nov 26 '14 at 05:25

Python: How to apply list comprehension to make list of lambdas?

1 Answers1