Remove Square Bracket and Breakdown List elements

Question

Here is my list.

[['john'],
 ['tom','peter'],
 ['sam'],
 ['mary','susan','dan'],
   :
 ['tony']]

I would like to remove all the square brackets and break down the list that looks like below.

['john',
 'tom',
 'peter',
 'sam',
 'mary',
 'susan',
 'dan',
   :
 'tony']

I tried to use new_lst = ','.join(str(v) for v in lst) and (','.join(lst)) but they don't work. And I couldn't think of a way to break down those list elements as well. That will be great if you all have some ideas and approaches on how to do that.

Thanks!

What's that colon there exactly? This is not valid Python syntax. Is this code, or a text file with that content? Or are you just using : to mark elision? — joanis, Jan 20 '22 at 21:48
The short way is `out = list(x for y in lst for x in y)`. The tricky way is `out = sum(lst,[])`. — Tim Roberts, Jan 20 '22 at 21:48
It wasn't literally a typo; he was trying to express a vertical ellipsis. — Tim Roberts, Jan 20 '22 at 21:50
@joanis, the colon means there are more elements in the list but I just use colon to represent. Sorry for the confusion — CodingStark, Jan 20 '22 at 21:51
OK, thanks for the clarification. In retrospect, I should have guessed. :) — joanis, Jan 20 '22 at 21:52
@joanis No problem at all. I should have been more clear up front! ;D — CodingStark, Jan 20 '22 at 21:56

score 4 · Accepted Answer · answered Jan 20 '22 at 21:50

4

Two good ways:

out = list(x for y in lst for x in y)
...or...
out = sum(lst,[])

answered Jan 20 '22 at 21:50

Tim Roberts

48,973
4
21
30

It works perfectly. Thank you so much!!! – CodingStark Jan 20 '22 at 21:55

score 2 · Answer 2 · answered Jan 20 '22 at 21:50

2

Here is a quick way:

my_list = [['john'],
 ['tom','peter'],
 ['sam'],
 ['mary','susan','dan'],
 ['tony']]

# flatten the list
my_list = [item for sublist in my_list for item in sublist]
print(my_list)

answered Jan 20 '22 at 21:50

Mohammad

3,276
2
19
35

It works! Thank you so much! – CodingStark Jan 20 '22 at 21:55

Remove Square Bracket and Breakdown List elements

2 Answers2