Python: Remove every first element in a 2D-List

Question

i have list in python. For example Test=[[1,1],[1,2],[1,3],[1,4]]. Now i would like to create a 1D-List by removing every first number to get this: [1,2,3,4].

My current Code works just fine, however it is definitely not the most pythonic code. Could anyone give me a better code for the following? Perhaps a small explenation would be great, as i would like to understand how to programm in good pythonic code. :)


i=len(Test)
b=[]
a=0
for x in range (100):
        Test[a].remove(Test[a][0])
        b+=Test[a]
        a+=1
print(b)

greeting, Dominik

Why are you looping until 100? Where did this value come from? — TDG, Sep 23 '22 at 07:54
@TDG Ah sorry, that was supposed to be i. 100 was the length of the List. However it is clear that i is the same. Forgot to change that — Dominik, Sep 23 '22 at 07:59
The shown output doesn't really match the explained logic (if you remove the first item this should rather give `[[1], [2], [3], [4]]`, using `[x[1:] for x in test]`) — mozway, Sep 23 '22 at 08:02

score 0 · Answer 1 · answered Sep 23 '22 at 07:55

0

Using a list comprehension:

test = [[1, 1], [1, 2], [1, 3], [1, 4]]
output = [x[1] for x in test]
print(output)  # [1, 2, 3, 4]

answered Sep 23 '22 at 07:55

Tim Biegeleisen

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Eirini Kotzia · Accepted Answer · 2022-09-23T08:06:13.050

0

Test=[[1,1],[1,2],[1,3],[1,4]]
# Loop through list using list comprehension and select the second 
# item
Test2 = [i[1] for i in Test]
print(Test2)

edited Sep 23 '22 at 08:06

answered Sep 23 '22 at 07:55

Eirini Kotzia

136
6

2

Please, format your code properly. Also add some explanation – buran Sep 23 '22 at 07:55

Python: Remove every first element in a 2D-List

2 Answers2