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Programmation Python
Les compléments
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Classe « Series »
Signature de la méthode std
def std(self, axis: 'Axis | None' = None, skipna: 'bool' = True, ddof: 'int' = 1, numeric_only: 'bool' = False, **kwargs)
Description
help(Series.std)
Return sample standard deviation over requested axis.
Normalized by N-1 by default. This can be changed using the ddof argument.
Parameters
----------
axis : {index (0)}
For `Series` this parameter is unused and defaults to 0.
.. warning::
The behavior of DataFrame.std with ``axis=None`` is deprecated,
in a future version this will reduce over both axes and return a scalar
To retain the old behavior, pass axis=0 (or do not pass axis).
skipna : bool, default True
Exclude NA/null values. If an entire row/column is NA, the result
will be NA.
ddof : int, default 1
Delta Degrees of Freedom. The divisor used in calculations is N - ddof,
where N represents the number of elements.
numeric_only : bool, default False
Include only float, int, boolean columns. Not implemented for Series.
Returns
-------
scalar or Series (if level specified)
Notes
-----
To have the same behaviour as `numpy.std`, use `ddof=0` (instead of the
default `ddof=1`)
Examples
--------
>>> df = pd.DataFrame({'person_id': [0, 1, 2, 3],
... 'age': [21, 25, 62, 43],
... 'height': [1.61, 1.87, 1.49, 2.01]}
... ).set_index('person_id')
>>> df
age height
person_id
0 21 1.61
1 25 1.87
2 62 1.49
3 43 2.01
The standard deviation of the columns can be found as follows:
>>> df.std()
age 18.786076
height 0.237417
dtype: float64
Alternatively, `ddof=0` can be set to normalize by N instead of N-1:
>>> df.std(ddof=0)
age 16.269219
height 0.205609
dtype: float64
Vous êtes un professionnel et vous avez besoin d'une formation ?
Programmation Python
Les fondamentaux
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