Python finding new element in list

Question

I want to find the new word in liste2.

liste1 = [['euro2016', '99'], ['portugal', '87'], ['ronaldo', '34']]
liste2 = [['euro2016', '90'], ['portugal', '75'], ['ronaldo', '44'], ['nani', '15']]


l1 = len(liste1)
l2 = len(liste2)

for x in range(0,l2):
    for y in range(0,l1):
        if liste2[x][0] not in liste1[y][0]:
            print liste2[x][0]

but my code is giving result like that :

euro2016

euro2016

portugal

portugal

ronaldo

ronaldo

nani

nani

nani

I guess I have to search liste1[all][0] but I dont know how to it.

What does `new` mean? your question is not clear. – DeepSpace Jul 13 '16 at 08:57 — DeepSpace, Jul 13 '16 at 08:57
Do you want the program just to return `nani`? – Bhargav Rao Jul 13 '16 at 08:58 — Bhargav Rao, Jul 13 '16 at 08:58

score 1 · Answer 1 · answered Jul 13 '16 at 09:02

1

check here

[i for i in liste2 if i[0] not in [j[0] for j in liste1]]

answered Jul 13 '16 at 09:02

Matroskin

429
4
5

score 1 · Accepted Answer · answered Jul 13 '16 at 09:02

I want to find the new word in liste2

You can use a list comprehension and apply a filter that takes only new items in liste2:

result = [i[0] for i in liste2 if i[0] not in (j[0] for j in liste1)]
#                              ^      filtering is done here       ^
print(result)
# ['nani']

score 0 · Answer 3 · answered Jul 13 '16 at 09:04

0

In [8]: dict1 = dict(liste1)

In [9]: dict2 = dict(liste2)

In [10]: print(set(dict2.keys()) - set(dict1.keys()))
set(['nani'])

answered Jul 13 '16 at 09:04

Dean Fenster

2,345
1
18
27

score 0 · Answer 4 · answered Jul 13 '16 at 09:09

You can create a set of the first element in each list item, and then take the difference. It will return the item in liste2 which is not in liste1:

l3 = set(map(lambda x:x[0],liste1))
l4 = set(map(lambda x: x[0],liste2))
print list(l4.difference(l3))[0]

Output:

nani
>>>

Python finding new element in list

4 Answers4