python - subset with multiple condictions code example

Example 1: or condition in pandas

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

Example 2: how to slicing dataframe using two conditions

# when you wrap conditions in parantheses, you give order
# you do those in brackets first before 'and'
# AND
movies[(movies.duration >= 200) & (movies.genre == 'Drama')]