Pandas count rows where, pandas count rows by condition, pandas row count by condition, pandas conditional row count, pandas count where

import pandas as pd

csv = pd.read_csv('data.csv')

cnt = len(csv[csv['Age'] == 22]) 
print(cnt) #outputs number of rows where age is 22

cnt = len(csv[(csv['Age'] == 22) & (csv['Sex'] == 'female')])
print(cnt) #outputs number of rows where age is 22 and sex is female

cnt = len(csv[(csv['Age'] < 10) | (csv['Age'] > 30 )])
print(cnt) #outputs number of rows where age is less than 10 or greater than 30