CODEWITHSUNDEEP
pythonpandasnumpy
Hardik Gupta
Hardik Gupta

Reputation: 4790

Apply a function to series of list without apply in pandas

I have a dataframe

df = pd.DataFrame({'Binary_List': [[0, 0, 1, 0, 0, 0, 0],
                                   [0, 1, 0, 0, 0, 0, 0],
                                   [0, 0, 1, 1, 0, 0, 0],
                                   [0, 0, 0, 0, 1, 1, 1]]})
df

    Binary_List
0   [0, 0, 1, 0, 0, 0, 0]
1   [0, 1, 0, 0, 0, 0, 0]
2   [0, 0, 1, 1, 0, 0, 0]
3   [0, 0, 0, 0, 1, 1, 1]

I want to apply a function to each list, without use of apply because apply is very slow when running on large dataset

def count_one(lst):
    index = [i for i, e in enumerate(lst) if e != 0]
    # some more steps 
    return len(index)

df['Value'] = df['Binary_List'].apply(lambda x: count_one(x))
df

    Binary_List             Value
0   [0, 0, 1, 0, 0, 0, 0]   1
1   [0, 1, 0, 0, 0, 0, 0]   1
2   [0, 0, 1, 1, 0, 0, 0]   2
3   [0, 0, 0, 0, 1, 1, 1]   3

I tried using this, but no improvement

vfunc = np.vectorize(count_one)
df['Value'] = vfunc(df['Binary_List'])

This gives me error

df['Value'] = count_one(df['Binary_List'])

Upvotes: 1

Views: 353

Answers (2)

Dev Khadka
Dev Khadka

Reputation: 5451

for getting length of list items you can use str function like below

df = pd.DataFrame({'Binary_List': [[0, 0, 1, 0, 0, 0, 0],
                                   [0, 1, 0, 0, 0, 0, 0],
                                   [0, 0, 1, 1, 0, 0, 0],
                                   [0, 0, 0, 0, 1, 1, 1]]})

df["Binary_List"].astype(np.str).str.count("1")

Upvotes: 1

ansev
ansev

Reputation: 30920

you can try DataFrame.explode:

df.explode('Binary_List').reset_index().groupby('index').sum()

        Binary_List
index   
0        1
1        1
2        2
3        3

Also you can do:

pd.Series([np.array(key).sum() for key in df['Binary_List']])
0    1
1    1
2    2
3    3
dtype: int64

Upvotes: 1

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