pandas set value by condition code example

Example 1: set value based on column

df.loc[df['c1'] == 'Value', 'c2'] = 10

Example 2: make a condition statement on column pandas

df.loc[df['column name'] condition, 'new column name'] = 'value if condition is met'

Example 3: if condition dataframe python

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