Python filtering in a list of lists by partial string

Question

Newbie question here...

I have a list of lists and I need to filter out entire elements (rows) if one occurrence of a partial string in a row exists.

E.g.

df = [['frog','womble','badger'], ['frog','ant','owl'], ['frog','badger','dataERRORdata']]

I need to search on %ERROR% (because the surrounding text is large and changeable) and for that to remove the entire element, leaving;

[['frog','womble','badger'], ['frog','ant','owl']]

I've tried a few list comprehensive/generator type loops but can't get it work. Would be quite useful to have an example just based on the above so I can tweak it to the specific case I have.

Feels like this is simple and I'm just missing something easy

Thanks!

check the in operator

yatu
– yatu

2020-03-30 16:41:37 +00:00
Commented Mar 30, 2020 at 16:41 — yatu
– yatu, Commented Mar 30, 2020 at 16:41

Cory Kramer · Accepted Answer · 2020-03-30 16:42:04Z

3

You can use a generator expression within all to check each sublist for a string containing 'ERROR', the use a list comprehension to loop over those sublists to filter.

>>> [sub for sub in df if all('ERROR' not in s for s in sub)]
[['frog', 'womble', 'badger'], ['frog', 'ant', 'owl']]

answered Mar 30, 2020 at 16:42

Cory Kramer

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user2390182 · Accepted Answer · 2020-03-30 16:48:27Z

3

This comprehension with any will do:

df = [['frog','womble','badger'],['frog','ant','owl'],['frog','badger','dataERRORdata']]

clean = [sub for sub in df if not any('ERROR' in w for w in sub)]
# [['frog', 'womble', 'badger'], ['frog', 'ant', 'owl']]

This is short-hand for the following nested loop (docs on for-else):

clean = []
for sub in df:
    for w in sub:
        if 'ERROR' in w:
            break
    else:  # loop not broken out of
        clean.append(sub)

edited Mar 30, 2020 at 16:48

answered Mar 30, 2020 at 16:42

user2390182

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