Python excluding indexes from array

Question

I have an array

a=[0, 10, 20, 30, 40, 50, 60]

I selected the 2nd and 3rd element with

a[[1,2]]

obtaining

array([10, 20])

How do I select the other elements of a except the elements I've already selected?

That is, I want to obtain:

array([0, 30, 40, 50, 60])

Logically, should be something like

a[![1,2]]

There is a filter function that does that => [here](https://docs.python.org/3/library/functions.html#filter). You can just Google, "Python 3 filter". — mutantkeyboard, Dec 01 '17 at 11:53
`a` as shown (but not named) is a list. `a[[1,2]]` gives an error. If `a` really is a numpy array, you should show that in your code. — hpaulj, Dec 01 '17 at 18:00

Patrick Artner · Answer 1 · 2020-01-19T09:39:29.163

1

Like this:

a=[0, 10, 20, 30, 40, 50, 60]

b = a[1:3]
c =[x for x in a if x not in b]

print(a)
print(b)
print(c)

Output:

[0, 10, 20, 30, 40, 50, 60]
[10, 20]
[0, 30, 40, 50, 60]

If order does not matter, you can stuff the list in a set and use these set operations: yourSet.union(otherSet) , yourSet.intersect(otherSet) , yourSet.difference(otherSet) , etc

edited Jan 19 '20 at 09:39

answered Dec 01 '17 at 11:54

Patrick Artner

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This uses plain old Python. – Mateen Ulhaq Dec 01 '17 at 12:00
@MateenUlhaq yes? If you have numpy and a hammer and see a nail - what would you do? – Patrick Artner Dec 01 '17 at 12:58
Smack it with the numpy of course! – Mateen Ulhaq Dec 01 '17 at 14:11

score 0 · Answer 2 · answered Dec 01 '17 at 11:54

0

In case on python 2.7, the easiest solution is that:

a=[0, 10, 20, 30, 40, 50, 60]
c=[1,2]
values = [a[i] for i, x in enumerate(a) if i not in c]
print values
[0, 30, 40, 50, 60]

answered Dec 01 '17 at 11:54

Víctor López

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Python excluding indexes from array

2 Answers2