Make one liner code for list unstacking in Python

Question

max_depth = [[i]*36 for i in range(1,11)]
max_depth = [j for k in max_depth for j in k]

I want to convert the above code in one line.

Answer 1

Instead of creating a nested list with [i]*36 , add another for to retrieve i 36 times:

[i for i in range(1,11) for _ in range(36)]

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Which would be equivalent to:

max_depth = []
for i in range(11):
    for _ in range(36):
        max_depth.append(i)

Answer 2

Using the itertools module:

from itertools import chain

max_depth = list(chain.from_iterable([i]*36 for i in range(1,11)))

Going one step further with itertools ,

from itertools import chain, repeat

max_depth = list(chain.from_iterable(repeat(i, 36) for i in range(1,11)))

Answer 3

最直接的解决方案：

[j for k in [[i]*36 for i in range(1,11)] for j in k]