Two values in list comprehension

Question

I attempted this list comprehension:

[sqrt(x), x**2 for x in range(rng)]

but apparently this syntax doesn't work. I suppose I could do something like this:

[fn(x), fn(x) for x in range(rng) for fn in (sqrt(), lambda x: x**2)]

but is there no cleaner way?

Edit: let's say rng is 3. I'd want an output of [0, 0, 1, 1, √2, 4]

"doesn't work" is not a problem specification. Touch the MCVE checkpoints, please: post both expected and actual results. — Prune
– Prune, Commented May 16, 2019 at 23:32

Ned Batchelder · Accepted Answer · 2019-05-16 23:34:16Z

You have a few options:

[fx for x in range(rng) for fx in [sqrt(x), x**2]]

or:

list(itertools.chain.from_iterable([sqrt(x), x**2] for x in range(rng)))

sanyassh · Accepted Answer · 2019-05-16 23:33:48Z

You can use double for-loop:

from math import sqrt rng = 3 print([item for x in range(rng) for item in (sqrt(x), x**2)]) # [0.0, 0, 1.0, 1, 1.4142135623730951, 4]

2 Answers 2