select rows by condition in another dataframe pandas code example

Example 1: 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]

Example 2: return rows based on column

df.loc[df['column_name'] != some_value]