Query a pandas dataframe without header

Question

I have a pandas DataFrame with no header and I have to assign string type names to the columns to be able to use the pandas query() method.

df.columns = ['A', 'B', 'C']
df.query('A > 0')

I'm wondering how can I query a DateFarame with no header?

df.query('A > 0') returns the rows in df in which the value of column A is greater than 0. — kiasari
– kiasari, Commented May 7, 2021 at 13:18

Laurent · Accepted Answer · 2021-05-07 14:29:16Z

4

As per Pandas documentation, when using query: "You can refer to variables in the environment by prefixing them with an ‘@’ character"

So, just as when your dataframe has a header ('A', 'B', ...), df.query('A > 0') is equivalent to df.query("@df['A'] > 0")

When you dataframe has no header, you can query like this: df.query("@df[0] > 0") ('0' for 'A', '1' for 'B', ...).

answered May 7, 2021 at 13:43

Laurent

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