where condition in pandas dataframe code example

Example 1: or condition in pandas

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

Example 2: or condition in pandas

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

Example 3: make a condition statement on column pandas

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

Example 4: new dataframe based on certain row conditions

# Create variable with TRUE if nationality is USA
american = df['nationality'] == "USA"

# Create variable with TRUE if age is greater than 50
elderly = df['age'] > 50

# Select all cases where nationality is USA and age is greater than 50
df[american & elderly]