在熊猫python中按列计算匹配部分字符串的出现次数

Question

new_data is a pandas dataframe with 4 columns and:

If I want to get a count of occurrences for an exact matching by column I do this:

new_data[new_data == 'blank'].count()

Output:

A          0
B          0
C          0
D          2654

What if I want a partial match for the string 'bla', would be something like this:

new_data[new_data in 'bla'].count()

But of course that does not work. What is the right way to do it?

Answer 1

Use DataFrame.apply and Series.str.contains with sum for count True s:

np.random.seed(1234)

new_data = pd.DataFrame(np.random.choice(['a blas', 's'], size=(2,4)), columns=list('ABCD'))
print (new_data)
        A       B       C  D
0       s       s  a blas  s
1  a blas  a blas  a blas  s

print (new_data.apply(lambda x: x.str.contains('bla')).sum())
A    1
B    1
C    2
D    0
dtype: int64

Your solution:

print (new_data[new_data.apply(lambda x: x.str.contains('bla'))].count())
A    1
B    1
C    2
D    0
dtype: int64