use if in pandas code example

Example 1: if condition dataframe python

df.loc[df['age1'] - df['age2'] > 0, 'diff'] = df['age1'] - df['age2']

Example 2: pandas if python

import pandas as pd

names = {'First_name': ['Jon','Bill','Maria','Emma']}
df = pd.DataFrame(names,columns=['First_name'])

df.loc[(df['First_name'] == 'Bill') | (df['First_name'] == 'Emma'), 'name_match'] = 'Match'  
df.loc[(df['First_name'] != 'Bill') & (df['First_name'] != 'Emma'), 'name_match'] = 'Mismatch'  

print (df)

Example 3: pandas if python

df['new column name'] = df['column name'].apply(lambda x: 'value if condition is met' if x condition else 'value if condition is not met')