pandas.DataFrame.eval

DataFrame.eval(expr, inplace=None, **kwargs)

Evaluate an expression in the context of the calling DataFrame instance.

Parameters:

expr : string

The expression string to evaluate.

inplace : bool

If the expression contains an assignment, whether to return a new DataFrame or mutate the existing.

WARNING: inplace=None currently falls back to to True, but in a future version, will default to False. Use inplace=True explicitly rather than relying on the default.

New in version 0.18.0.

kwargs : dict

See the documentation for eval() for complete details on the keyword arguments accepted by query().

Returns:

ret : ndarray, scalar, or pandas object

See also

pandas.DataFrame.query, pandas.DataFrame.assign, pandas.eval

Notes

For more details see the API documentation for eval(). For detailed examples see enhancing performance with eval.

Examples

>>> from numpy.random import randn
>>> from pandas import DataFrame
>>> df = DataFrame(randn(10, 2), columns=list('ab'))
>>> df.eval('a + b')
>>> df.eval('c = a + b')