How can I replace a text delimited string list item with multiple list items in a python list?

Question

Given a list:

mylist = [\'dog\', \'cat\', \'mouse_bear\', \'lion_tiger_rabbit\', \'ant\']

I\'d like a one-liner to return a new list:

Answer 1

One-liners are over-rated. Here's a solution using a "traditional" for loop.

mylist = ['dog', 'cat', 'mouse_bear', 'lion_tiger_rabbit', 'ant']

out = []
for s in mylist:
    if '_' in s:
        out.extend(s.split('_'))
    else:
        out.append(s)

print(out)

output

['dog', 'cat', 'mouse', 'bear', 'lion', 'tiger', 'rabbit', 'ant']

This also works:

out = []
for s in mylist:
    out.extend(s.split('_'))

It's shorter, but I think the previous version is clearer.

Answer 2

You can try this:

from itertools import chain

mylist = ['dog', 'cat', 'mouse_bear', 'lion_tiger_rabbit', 'ant']

new_list = list(chain(*[[i] if "_" not in i else i.split("_") for i in mylist]))

Output:

['dog', 'cat', 'mouse', 'bear', 'lion', 'tiger', 'rabbit', 'ant']

Answer 3

mylist = ['dog', 'cat', 'mouse_bear', 'lion_tiger_rabbit', 'ant']
animals = [a for item in mylist for a in item.split('_')]
print (animals)

Answer 4

This is not a one liner, but is nevertheless a valid option to consider if you want to return a generator:

def yield_underscore_split(lst):
     for x in lst:
         yield from x.split('_')

>>> list(yield_underscore_split(mylist))
['dog', 'cat', 'mouse', 'bear', 'lion', 'tiger', 'rabbit', 'ant']

---

Original answer valid only for versions Python 3.3-3.7, kept here for interested readers. Do not use!

>>> list([(yield from x.split('_')) for x in l]) 
['dog', 'cat', 'mouse', 'bear', 'lion', 'tiger', 'rabbit', 'ant']

Answer 5

Split each item into sublists and flatten them:

[item for sublist in mylist for item in sublist.split("_")]

Answer 6

what I would actually do:

newlist = []

for i in mylist:
    newlist += i.split('_')