pandas create column based on condition code example
Example 1: make a condition statement on column pandas
df['color'] = ['red' if x == 'Z' else 'green' for x in df['Set']]
Example 2: pandas create a new column based on condition of two columns
conditions = [
df['gender'].eq('male') & df['pet1'].eq(df['pet2']),
df['gender'].eq('female') & df['pet1'].isin(['cat', 'dog'])
]
choices = [5,5]
df['points'] = np.select(conditions, choices, default=0)
print(df)
gender pet1 pet2 points
0 male dog dog 5
1 male cat cat 5
2 male dog cat 0
3 female cat squirrel 5
4 female dog dog 5
5 female squirrel cat 0
6 squirrel dog cat 0
Example 3: pandas create new column conditional on other columns
conditions = [
(df['Base Column 1'] == 'A') & (df['Base Column 2'] == 'B'),
(df['Base Column 3'] == 'C')]
choices = ['Conditional Value 1', 'Conditional Value 2']
df['New Column'] = np.select(conditions, choices, default='Conditional Value 1')
Example 4: make a condition statement on column pandas
df.loc[df['column name'] condition, 'new column name'] = 'value if condition is met'
Example 5: add a value to an existing field in pandas dataframe after checking conditions
gapminder['gdpPercap_ind'] = gapminder.gdpPercap.apply(lambda x: 1 if x >= 1000 else 0)
gapminder.head()