Selecting with complex criteria from pandas.DataFrame

Question

For example I have simple DF:

import pandas as pd
from random import randint

df = pd.DataFrame({\'A\': [randint(1, 9) for x in xrange(10)],
                         


        

Answer 1

And remember to use parenthesis!

Keep in mind that & operator takes a precedence over operators such as > or < etc. That is why

4 < 5 & 6 > 4

evaluates to False. Therefore if you're using pd.loc, you need to put brackets around your logical statements, otherwise you get an error. That's why do:

df.loc[(df['A'] > 10) & (df['B'] < 15)]

instead of

df.loc[df['A'] > 10 & df['B'] < 15]

which would result in

TypeError: cannot compare a dtyped [float64] array with a scalar of type [bool]