Pandas DataFrame query() Method
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).
