list augmentation in python with numpy or other library

Question

I would like to augment list from

[1, 2, 3, 4, 5]

to

[1, 1, 2, 2, 3, 3, 4, 4, 5, 5]

If I want to augment likewise n times (like 100 or 500 times), how can I do it? I do not want to do it with regular loop, but using some library like numpy. Any helps?

Many thanks.

With only itertools you could do `list(chain.from_iterable(repeat(x, 2) for x in a))`. — Paul Rooney, Mar 11 '19 at 09:50
user3483203 marked my question as duplicate and the answer is what I wanted to know. yatu also answered to my question as well; Thanks to you all. — Isaac Sim, Mar 12 '19 at 00:56

score 2 · Accepted Answer · answered Mar 11 '19 at 09:25

2

You can do this with numpy's np.repeat:

import numpy as np
a = np.array([1, 2, 3, 4, 5])
np.repeat(a,2)
# array([1, 1, 2, 2, 3, 3, 4, 4, 5, 5])

answered Mar 11 '19 at 09:25

yatu

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Please flag obvious duplicates like this as such rather than answering. – user3483203 Mar 11 '19 at 09:48
user3483203 // I expected it to be duplicate but I asked the question just because I couldn't find one with the keywords that I thought to be related. Sorry for asking a duplicate question. – Isaac Sim Mar 12 '19 at 00:54

list augmentation in python with numpy or other library

1 Answers1