Pandas query function not working with spaces in column names

Question

I have a dataframe with spaces in column names. I am trying to use query method to get the results. It is working fine with \'c\' column but getting error for \

Answer 1

Pandas 0.25+

As described here:

DataFrame.query() and DataFrame.eval() now supports quoting column names with backticks to refer to names with spaces (GH6508)

So you can use:

a.query('`a b`==5')

Pandas pre-0.25

You cannot use pd.DataFrame.query if you have whitespace in your column name. Consider what would happen if you had columns named a, b and a b; there would be ambiguity as to what you require.

Instead, you can use pd.DataFrame.loc:

df = df.loc[df['a b'] == 5]

Since you are only filtering rows, you can omit .loc accessor altogether:

df = df[df['a b'] == 5]