Python pandas dataframe group by based on a condition
90,487
Solution 1
The grouped result is a regular DataFrame, so just filter the results as usual:
import pandas as pd
df = pd.DataFrame({'a': ['a', 'b', 'a', 'a', 'b', 'c', 'd']})
after = df.groupby('a').size()
>> after
a
a 3
b 2
c 1
d 1
dtype: int64
>> after[after > 2]
a
a 3
dtype: int64
Solution 2
Try this code:
df.groupby('column').filter(lambda group: group.size > X)
Comments
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ahajib almost 2 years
My question is simple, I have a dataframe and I
groupby
the results based on a column and get the size like this:df.groupby('column').size()
Now the problem is that I only want the ones where size is greater than X. I am wondering if I can do it using a lambda function or anything similar? I have already tried this:
df.groupby('column').size() > X
and it prints out some True and False values.