count dataframe colmn value on specific condition

Question

I have a data frame df as below and I want to count how many scores are greater than 10 in df score column.

data in dataframe df is like :

code score   
A    11      
B    9     
c    14    
D    11   

and as output I want 3.

Answer 1

Use sum of boolean mask - count Trues values like 1s:

out = df['score'].gt(10).sum()
#or
#out = (df['score'] > 10).sum()
print (out)
3