CODEWITHSUNDEEP
pythonpandas
jm96
jm96

Reputation: 57

Count occurrence of element in column of lists panda dataframe

I have a data frame that has a column of lists of strings, I want to find the number of occurrences of a string in the column.

i.e

         samples  subject  trial_num
0    ['aa','bb']        1          1
1    ['bb','cc']        1          2

I want to get 2 for 'bb' 1 for 'aa' and 'cc'

Upvotes: 1

Views: 84

Answers (1)

ansev
ansev

Reputation: 30940

Use:

df['samples'].explode().value_counts().to_dict()
#{'bb': 2, 'aa': 1, 'cc': 1}

Or without explode:

pd.Series(np.concatenate(df['samples'])).value_counts().to_dict()
#{'bb': 2, 'aa': 1, 'cc': 1}

Solution only with numpy

dict(zip(*np.unique(np.concatenate(df['samples']), return_counts=True)))
#{'bb': 2, 'aa': 1, 'cc': 1}

Upvotes: 2

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