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Pandas DataFrame query() Method

❮ DataFrame Reference


Example

Return the rows where age is over 35:

import pandas as pd

data = {
  "name": ["Sally", "Mary", "John"],
  "age": [50, 40, 30]
}

df = pd.DataFrame(data)

print(df.query('age > 35'))
Try it Yourself »

Definition and Usage

The query() method allows you to query the DataFrame.

The query() method takes a query expression as a string parameter, which has to evaluate to either True of False.

It returns the DataFrame where the result is True according to the query expression.


Syntax

dataframe.query(expr, inplace)

Parameters

The inplace paramater is a keyword argument.

Parameter Values Description
expr Required. A string that represents a query expression.
inplace True|False Optional. A boolean value that specifies if the query() method should leave the original DataFrame untouched and return a copy (inplace = False). This is Default.
Or:
Make the changes in the original DataFrame (inplace = True)

Return Value

A DataFrame with the new result, or None if the changes were made in the original DataFrame (inplace = True).


❮ DataFrame Reference