Count all items in the list in dataframe (Python)

Question

I have a dataframe that hs 2 columns

Text           Categories
"Hi Hello"     [F35, B3, C98]
"Where is"     [G58, F35, C17]
"Is she?!"     [T92, F35, B3]

the field Categories is an array of Categories

I want to find how many distinct Categories I have

I tried this code but did not work

print(len(sorted(set(df['Categories']))))

I tried this but it was just for one record !

print(len(sorted(set(df['Categories'][0]))))

I did not know how to do it for all categories in the dataframe?

Are you searching for unique values within each array, or are you searching for unique values for each Category across all arrays? — Louis
– Louis, Commented Jul 12, 2020 at 10:48

bigbounty · Accepted Answer · 2020-07-12 11:02:57Z

2

This should give you unique categories.

In [128]: df = pd.DataFrame({
     ...:     'Text': ["Hi Hello", "Where is","Is she?!"],
     ...:     'Categories': [["F35", "B3", "C98"],["G58", "F35", "C17"],["G58", "F35", "C17"]]
     ...: })
In [131]: set(df["Categories"].explode())
Out[131]: {'B3', 'C17', 'C98', 'F35', 'G58'}

Credits to @DanielGeffen - You can also use df["Categories"].explode().unique()

edited Jul 12, 2020 at 11:02

answered Jul 12, 2020 at 10:51

bigbounty

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1 Comment

Daniel Geffen Over a year ago

You can also use pandas unique function instead of set: df["Categories"].explode().unique()

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