scipy.stats.mode#
- scipy.stats.mode(a, axis=0, nan_policy='propagate', keepdims=None)[source]#
Return an array of the modal (most common) value in the passed array.
If there is more than one such value, only one is returned. The bin-count for the modal bins is also returned.
- Parameters
- aarray_like
n-dimensional array of which to find mode(s).
- axisint or None, optional
Axis along which to operate. Default is 0. If None, compute over the whole array a.
- keepdimsbool, optional
If set to
False
, the axis over which the statistic is taken is consumed (eliminated from the output array) like other reduction functions (e.g.skew
,kurtosis
). If set toTrue
, the axis is retained with size one, and the result will broadcast correctly against the input array. The default,None
, is undefined legacy behavior retained for backward compatibility.Warning
Unlike other reduction functions (e.g.
skew
,kurtosis
), the default behavior ofmode
usually retains the the axis it acts along. In SciPy 1.11.0, this behavior will change: the default value of keepdims will becomeFalse
, the axis over which the statistic is taken will be eliminated, and the valueNone
will no longer be accepted.- nan_policy{‘propagate’, ‘raise’, ‘omit’}, optional
Defines how to handle when input contains nan. The following options are available (default is ‘propagate’):
‘propagate’: treats nan as it would treat any other value
‘raise’: throws an error
‘omit’: performs the calculations ignoring nan values
- Returns
- modendarray
Array of modal values.
- countndarray
Array of counts for each mode.
Notes
The mode of object arrays is calculated using
collections.Counter
, which treats NaNs with different binary representations as distinct.Deprecated since version 1.9.0: Support for non-numeric arrays has been deprecated as of SciPy 1.9.0 and will be removed in 1.11.0. pandas.DataFrame.mode can be used instead.
The mode of arrays with other dtypes is calculated using
numpy.unique
. In NumPy versions 1.21 and after, all NaNs - even those with different binary representations - are treated as equivalent and counted as separate instances of the same value.Examples
>>> a = np.array([[6, 8, 3, 0], ... [3, 2, 1, 7], ... [8, 1, 8, 4], ... [5, 3, 0, 5], ... [4, 7, 5, 9]]) >>> from scipy import stats >>> stats.mode(a, keepdims=True) ModeResult(mode=array([[3, 1, 0, 0]]), count=array([[1, 1, 1, 1]]))
To get mode of whole array, specify
axis=None
:>>> stats.mode(a, axis=None, keepdims=True) ModeResult(mode=array([3]), count=array([3])) >>> stats.mode(a, axis=None, keepdims=False) ModeResult(mode=3, count=3)