CODEWITHSUNDEEP
pythonlistpython-3.x
user2131116
user2131116

Reputation: 2861

How to use discontinuous index to form a new list in python?

If I have a list for example

A = [0.54,13,18,0,1,1,1,1,0,0,0,1,0]

and I want A[0:1] and A[3:] to form

[0.54, 0, 1, 1, 1, 1, 0, 0, 0, 1, 0]

I know if I want a continuous segment in a list , I can do by list[start:end]

but if I want to use several index range in a list but these segments are not continuous, Can I using

list[ ? ] to achieve?

it seems I can do by A[range1] + A[range2]

thanks

Upvotes: 2

Views: 4342

Answers (3)

thefourtheye
thefourtheye

Reputation: 239473

You can use list comprehension to achieve this.

A = [0.54,13,18,0,1,1,1,1,0,0,0,1,0]
ranges = [(1, 3), (5, 8), (11, 14)]
print ([item for start, end in ranges for item in A[start:end]])

Output

[13, 18, 1, 1, 1, 1, 0]

Upvotes: 7

RyPeck
RyPeck

Reputation: 8147

Simple enough... You are already doing this. Anything else just adds unnecessary fluff. Not sure if there are any performance gains to be had.

>>> A[2:4] + A[7:9]
[18, 0, 1, 0]

To get just one item... Splice just one into a list.

>>> A[2:4] + A[7:9] + A[3:3]
[18, 0, 1, 0]

Upvotes: 2

iruvar
iruvar

Reputation: 23364

itertools may help

from itertools import chain
A = [0.54,13,18,0,1,1,1,1,0,0,0,1,0]
list(chain(A[1:4], A[5:7], A[8:10]))
[13, 18, 0, 1, 1, 0, 0]

Upvotes: 4

Related Questions