计算熊猫数据框列中满足条件的单元格数

Question

Hi I have following dataframe

Name Gender Age
ABC  M      21
C-DF F      24

I have to count the number of cells having a dash in them. I used the regular expression and wrote the code written below

df[df['Name'] == r'-+'].sum()

The output that I am getting is. I don't understand what mistake did I do or if I wrote the wrong command.

Name             0.0
Gender           0.0
Age              0.0
dtype: float64

Please help. Thanks.

Answer 1

Use contains for boolean mask with sum - True s are processes like 1 s:

print (df)
   Name Gender  Age
0  AB+C      M   21
1  C-DF      F   24

a = df['Name'].str.contains(r'-').sum()
print (a)
1