dataframe where condition code example

Example 1: or condition in pandas

df1 = df[(df.a != -1) & (df.b != -1)]

Example 2: or condition in pandas

df2 = df[(df.a != -1) | (df.b != -1)]

Example 3: pandas where

# replaces values with other where condition is False
DataFrame.where(cond, other=nan, inplace=False, axis=None, level=None, errors='raise', try_cast=False)

import pandas as pd 
df = pd.DataFrame({'values':[1,2,3,4]})

df.where(df['values'] % 2 == 0, -1) # output : [-1, 2, -3, 4]

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: conditions in pandas dataframe

from pandas import DataFrame
  
names = {'First_name': ['Hanah', 'Ria', 'Jay', 'Bholu', 'Sachin']}
df = DataFrame(names, columns =['First_name'])
  
df['Status'] = df['First_name'].apply(lambda x: 'Found' if x == 'Ria' else 'Not Found')
  
print (df)

Example 6: if condition dataframe python

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