scipy.stats.

trim1#

scipy.stats.trim1(a, proportiontocut, tail='right', axis=0)[source]#

Slice off a proportion from ONE end of the passed array distribution.

If proportiontocut = 0.1, slices off ‘leftmost’ or ‘rightmost’ 10% of scores. The lowest or highest values are trimmed (depending on the tail). Slice off less if proportion results in a non-integer slice index (i.e. conservatively slices off proportiontocut ).

Parameters:

aarray_like: Input array.
proportiontocutfloat: Fraction to cut off of ‘left’ or ‘right’ of distribution.
tail{‘left’, ‘right’}, optional: Defaults to ‘right’.
axisint or None, optional: Axis along which to trim data. Default is 0. If None, compute over the whole array a.

Returns:

trim1ndarray: Trimmed version of array a. The order of the trimmed content is undefined.

Notes

Array API Standard Support

trim1 has experimental support for Python Array API Standard compatible backends in addition to NumPy. Please consider testing these features by setting an environment variable SCIPY_ARRAY_API=1 and providing CuPy, PyTorch, JAX, or Dask arrays as array arguments. The following combinations of backend and device (or other capability) are supported.

Library	CPU	GPU
NumPy	✅	n/a
CuPy	n/a	⛔
PyTorch	⛔	⛔
JAX	⛔	⛔
Dask	⛔	n/a

See Support for the array API standard for more information.

Examples

Create an array of 10 values and trim 20% of its lowest values:

>>> import numpy as np
>>> from scipy import stats
>>> a = [0, 1, 2, 3, 4, 5, 6, 7, 8, 9]
>>> stats.trim1(a, 0.2, 'left')
array([2, 4, 3, 5, 6, 7, 8, 9])

Note that the elements of the input array are trimmed by value, but the output array is not necessarily sorted.

The proportion to trim is rounded down to the nearest integer. For instance, trimming 25% of the values from an array of 10 values will return an array of 8 values:

>>> b = np.arange(10)
>>> stats.trim1(b, 1/4).shape
(8,)

Multidimensional arrays can be trimmed along any axis or across the entire array:

>>> c = [2, 4, 6, 8, 0, 1, 3, 5, 7, 9]
>>> d = np.array([a, b, c])
>>> stats.trim1(d, 0.8, axis=0).shape
(1, 10)
>>> stats.trim1(d, 0.8, axis=1).shape
(3, 2)
>>> stats.trim1(d, 0.8, axis=None).shape
(6,)