How to count the number of zeros if they lie between ones

August 10, 2023

I have dataframe

ID   A  B  C
60   0  1  1
120  0  1  1
180  0  1  1
240  0  0  0
300  0  0  0 
360  1  1  0
420  1  1  1
480  0  0  0
540  0  0  0 
600  0  0  0
660  0  0  0
720  1  1  1
780  1  0  1
840  0  0  0
900  0  0  0

How to count the number of zeros only between 1

in this example, the answer should be [4] in A, [2,4] in B, [3,4] in C

Could you help me, please?

i have seen this option, but it does not fit, since it counts all zeros in a row. And I need to count zeros only between 1. Please help.

>Solution :

You can try something like bfill and ffill then groupby the result

s = (df.mask(df==0).ffill() == df.mask(df==0).bfill()) & (df==0)
s = s.apply(lambda x : x[x].groupby((~x).cumsum()).count().tolist())
ID        []
A        [4]
B     [2, 4]
C     [3, 4]
dtype: object