Pandas — Filtering

Boolean filtering

import pandas as pd

df = pd.DataFrame({'name': ['Alice', 'Bob', 'Charlie'], 'age': [25, 30, 35]})

# Single condition
print(df[df['age'] > 25])

# Multiple conditions
print(df[(df['age'] > 25) & (df['age'] < 35)])

isin

df = pd.DataFrame({'name': ['Alice', 'Bob', 'Charlie'], 'city': ['NYC', 'LA', 'Chicago']})
print(df[df['city'].isin(['NYC', 'LA'])])

query

print(df.query('age > 25'))
print(df.query('age > 25 and city == "NYC"'))

where

print(df.where(df['age'] > 25))

mask

print(df.mask(df['age'] > 25, other=0))

Mini Practice

1. Filter with conditions
2. Use isin for multiple values
3. Use query method
4. Apply where and mask

Up Next

Continue with Indexing - Index operations.