get list of 1st elements from table in one line of code [python]

Question

i have a python table like this

t = [
  ['a', 1, True],
  ['b', 2, True],
  ['c', 3, True],
  ['d', 4, True]
]

i want to extract the 1st element list like this

l = ['a', 'b', 'c', 'd']

i know how tod do it with a for loop, but i can't do it with one line of code, i've tried this

t[:][0]

and also this :

t[0][:]

but this does not give me what i need

Read about [list comprehensions](https://www.w3schools.com/python/python_lists_comprehension.asp). Tl;dr: `[v[0] for v in t]` — Yevhen Kuzmovych, Jul 13 '21 at 12:05
Also, does this answer your question? [Extract first item of each sublist](https://stackoverflow.com/questions/25050311/extract-first-item-of-each-sublist) — Yevhen Kuzmovych, Jul 13 '21 at 12:09
List Comprehension will work for this problem you can use the for loop in the same line. — Amit Baghel, Jul 13 '21 at 12:07

score 0 · Accepted Answer · answered Jul 13 '21 at 12:05

0

One option (and probably the fastest) is a list comprehension.

[ s[0] for s in t ]

answered Jul 13 '21 at 12:05

LaytonGB

score 0 · Answer 2 · edited Jul 13 '21 at 12:09

0

You can try this:

list(zip(*t))[0]

edited Jul 13 '21 at 12:09

answered Jul 13 '21 at 12:06

Krishna Rao

score 0 · Answer 3 · answered Jul 13 '21 at 12:13

You can use zip and unpack the list in it:

zip(*t)

Then convert that to a list:

new1=list(zip(*t))

This returns

[('a', 'b', 'c', 'd'), (1, 2, 3, 4), (True, True, True, True)]

Now you can simply fetch the first element of the list:

print(new1[0])

3 Answers3