pandas if else code example

Example 1: pandas if else

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

Example 2: pandas if python

import pandas as pd

numbers = {'set_of_numbers': [1,2,3,4,5,6,7,8,9,10]}
df = pd.DataFrame(numbers,columns=['set_of_numbers'])

df['equal_or_lower_than_4?'] = df['set_of_numbers'].apply(lambda x: 'True' if x <= 4 else 'False')

print (df)

Example 3: compute value based on condition of existing column dataframe

# create a list of our conditions
conditions = [
    (df['likes_count'] <= 2),
    (df['likes_count'] > 2) & (df['likes_count'] <= 9),
    (df['likes_count'] > 9) & (df['likes_count'] <= 15),
    (df['likes_count'] > 15)
    ]

# create a list of the values we want to assign for each condition
values = ['tier_4', 'tier_3', 'tier_2', 'tier_1']

# create a new column and use np.select to assign values to it using our lists as arguments
df['tier'] = np.select(conditions, values)

# display updated DataFrame
df.head()

Example 4: if condition dataframe python

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

Example 5: 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 6: 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')