using lambda in pd.apply() in pandas

Question

I have a pandas DataFrame with a column 'categories'. That column has list as elements and each list contains some words. I want to find in how many lists the words "pizza" or "Italian" appear. The columns look like: screenshot how the columns look like

I tried the code below, but I am getting everything as False.

business.categories.apply(lambda x: ('pizza' in x) or ("Italian" in x))

Please post the sample of your dataframe as text in the question, not as a picture. See [How to make good pandas examples](https://stackoverflow.com/questions/20109391/how-to-make-good-reproducible-pandas-examples) — G. Anderson, Jan 03 '20 at 20:19
Try `business.categories.apply(lambda x: {'italian', 'pizza'} < x)` — yatu, Jan 03 '20 at 20:20
I am not able to re-create this behavior locally creating my own example from your screenshot. As @G.Anderson if you post a sample of the dataframe into the question the community will be able to provide further help — sedavidw, Jan 03 '20 at 20:23

Kenan · Answer 1 · 2020-01-03T21:30:51.237

0

Dont use or use |

business['categories'].map(lambda x: ('pizza' in x) | ("Italian" in x))

pandas doesn't like and or or, use & or |

Something to note:

Make sure the values in your list don't have whitespaces, for example Italian and _Italian are different. If that's the case you have to do this in two pars

Cleaning

business['categories'] = business['categories'].map(lambda x: [i.strip() for i in x])

then map

business['categories'].map(lambda x: ('pizza' in x) | ("Italian" in x))

edited Jan 03 '20 at 21:30

answered Jan 03 '20 at 20:26

Kenan

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still getting all as False – Sahil Swaroop Jan 03 '20 at 20:28
please post the head of the dataframe so I can test – Kenan Jan 03 '20 at 20:29
but they do have white spaces now what to do ? – Sahil Swaroop Jan 03 '20 at 20:38
then of course you get all false, you have to remove that first before checking – Kenan Jan 03 '20 at 20:38
is there any way to remove all those white spaces – Sahil Swaroop Jan 03 '20 at 20:41
Use .strip() to remove whitespaces if i understand correctly business['categories'].map(lambda x: ('pizza' in x.strip()) | ("Italian" in x.strip())) – No_body Jan 03 '20 at 20:52
updated to account for white spaces, @No_body, your approach won't work because `x` is a `list` in `lambda` not `str` – Kenan Jan 03 '20 at 21:31

using lambda in pd.apply() in pandas

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