only keep certain rows pandas code example

Example 1: only keep rows of a dataframe based on a column value

df.loc[(df['column_name'] >= A) & (df['column_name'] <= B)]

Example 2: 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]