How to replace empty instance in list with Python?

Question

I want to replace empty instances '' with '.' in list compare:

compare = ['ŋsbluː', 'mən', '', 'blˈyːt', '', 'ʔˈɛs']
compare = [w.replace('', '.') for w in compare]

Output: ['.ŋ.s.b.l.u.ː.', '.m.ə.n.', '.', '.b.l.ˈ.y.ː.t.', '.', '.ʔ.ˈ.ɛ.s.]'

But I want: ['ŋsbluː', 'mən', '.', 'blˈyːt', '.', 'ʔˈɛs']

`print([i if i else "." for i in compare])` ? – Rakesh Jun 22 '18 at 15:11 — Rakesh, Jun 22 '18 at 15:11

score 2 · Answer 1 · answered Jun 22 '18 at 15:11

2

You're calling replace on the individual elements in the list. You can accomplish the desired effect by filtering through the list:

compare = ['ŋsbluː', 'mən', '', 'blˈyːt', '', 'ʔˈɛs']
compare = ["." if x == "" else x for x in compare]

answered Jun 22 '18 at 15:11

Benjamin Engwall

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You shouldn't use `x == ""` instead of `if not x` – Eli Korvigo Jun 22 '18 at 15:15
2

In the end, it all boils down to `[x if x else '.' for x in compare]` -> `[x or '.' for x in compare]` – Eli Korvigo Jun 22 '18 at 15:20
Yeah, that's a much cleaner way to do it. The user specifically said empty string, but it seems unlikely that they'd encounter `None` or other false-y values in this context. – Benjamin Engwall Jun 22 '18 at 15:42

score 2 · Answer 2 · answered Jun 22 '18 at 15:12

2

compare = [i or '.' for i in compare]

answered Jun 22 '18 at 15:12

Ali Aqrabawi

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score 1 · Answer 3 · edited Jul 02 '18 at 20:32

1

What you really mean is compare = ['.' if w == '' else w for w in compare] rather than replace which would replace every zero-length substring in your code.

But then you don't really need a list comprehension because it could also be in-place.

for i, x in enumerate(compare):
    if x == '':
        compare[i] = '.'

edited Jul 02 '18 at 20:32

Eli Korvigo

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answered Jun 22 '18 at 15:09

Blownhither Ma

1,461
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Isn't this identical to what he has in his question? – user3483203 Jun 22 '18 at 15:12
@user3483203 sorry, typo in editing – Blownhither Ma Jun 22 '18 at 15:14

How to replace empty instance in list with Python?

3 Answers3