def center(dataset, out=None):
return _preprocess(_center_fn, dataset, out)<EOL>
Returns a centered data set.

Each column of the returned data will have mean 0.
The row vector subtracted from each row to achieve this
transformation is also returned.

Parameters
----------
dataset : DataFrame or ndarray

out : DataFrame or ndarray, optional
    Alternate output array in which to place the result.
    If provided, it must have the same shape and type
    (DataFrame or ndarray) as the expected output.

Returns
----------
out : tuple of DataFrame or ndarray
    The output data is of the same type as the input.

Notes
----------
To exclude a column (such as a constant feature, which is
usually the first or last column of data) simply don't
include it in the input. For example:

>>> centered_data, means = pn.center(mydata.iloc[:, 1:])

To perform this operation in place:

>>> _, means = pn.center(mydata.iloc[:, 1:], out=mydata.iloc:, 1:])