How to delete repeated elements from array keeping the order unchanged in python?

Question

I have sequence of integer elements in array "a" ,given below

a=[2,1,5,4,8,4,2,1,2,4,8,6,1,5,4,87,62,3]

I need the output like

output=[2,1,5,4,8,6,87,62,3]

I tried the built-in functions like set or unique but it arrange the
resulting sequence in ascending order, I want to keep the order unchanged.

Can anyone help?

score 3 · Accepted Answer · answered Apr 10 '16 at 07:46

3

You can use sorted with key=list.index

>>> a=[2,1,5,4,8,4,2,1,2,4,8,6,1,5,4,87,62,3]
>>> new_a = sorted(set(a), key=a.index)
>>> new_a
[2, 1, 5, 4, 8, 6, 87, 62, 3]

answered Apr 10 '16 at 07:46

Hackaholic

thanks alot for quick response sir – faiz Apr 10 '16 at 07:54
i am using "numpy" so it gives error AttributeError: 'numpy.ndarray' object has no attribute 'index' what is this problem? – faiz Apr 10 '16 at 08:13

tushortz · Answer 2 · 2017-04-07T14:40:54.613

0

a=[2,1,5,4,8,4,2,1,2,4,8,6,1,5,4,87,62,3]  
b = []

You can use

[b.append(x) for x in a if x not in b]

or easier to read

for x in a:
    if x not in b:
        b.append(x)


>>> [2, 1, 5, 4, 8, 6, 87, 62, 3]`

edited Apr 07 '17 at 14:40

answered Apr 10 '16 at 07:46

tushortz

thanks alot for quick response sir – faiz Apr 10 '16 at 07:54
Sir can you please up vote my question, because i am banned from further queries.. thanks..@Tushortz – faiz May 24 '18 at 05:13

2 Answers2