CODEWITHSUNDEEP
pythonlistcompare
moatze
moatze

Reputation: 148

Add item to list if not already exists

I'm new to Python and got following problem:

a = [[0,abc,1],[0,def,1]]

b = [abc,jkl]

Output should be:

c = [[0,abc,1],[0,def,1],[0,jkl,1]]

Can anyone help me out there?

Upvotes: 2

Views: 20222

Answers (3)

Harpal
Harpal

Reputation: 12587

How about this?

>>> a = [[0,'abc',1],[0,'def',1]]
>>> b = ['abc','jkl']
>>> c = a[:]
>>> for i in b:
...     if [0,i,1] not in a:
...             c.append([0,i,1])
... 
>>> c
[[0, 'abc', 1], [0, 'def', 1], [0, 'jkl', 1]]

Upvotes: 3

Damián Montenegro
Damián Montenegro

Reputation: 839

It can be done with the following code:

In [3]: a = [[0,'abc',1],[0,'def',1]]
In [4]: b = ['abc','jkl']
In [5]: c = a[:]
In [6]: c.extend([[0,e,1] for e in b if e not in [x for _,x,_ in a]])
In [7]: c
Out[8]: [[0, 'abc', 1], [0, 'def', 1], [0, 'jkl', 1]]

Hope this helps!

Upvotes: 6

Uma Kanth
Uma Kanth

Reputation: 5629

Use not in to check if it contains or not

a = [[0,abc,1],[0,def,1]]

b = [abc,jkl]

c = []

for i in a:
    if i not in c:
       c.append(i)
for j in b:
    if j not in c:
       c.append(j)

Upvotes: 1

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