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Fonction quantile - module numpy.matlib

Signature de la fonction quantile

def quantile(a, q, axis=None, out=None, overwrite_input=False, interpolation='linear', keepdims=False) 

Description

quantile.__doc__

    Compute the q-th quantile of the data along the specified axis.

    .. versionadded:: 1.15.0

    Parameters
    ----------
    a : array_like
        Input array or object that can be converted to an array.
    q : array_like of float
        Quantile or sequence of quantiles to compute, which must be between
        0 and 1 inclusive.
    axis : {int, tuple of int, None}, optional
        Axis or axes along which the quantiles are computed. The
        default is to compute the quantile(s) along a flattened
        version of the array.
    out : ndarray, optional
        Alternative output array in which to place the result. It must
        have the same shape and buffer length as the expected output,
        but the type (of the output) will be cast if necessary.
    overwrite_input : bool, optional
        If True, then allow the input array `a` to be modified by intermediate
        calculations, to save memory. In this case, the contents of the input
        `a` after this function completes is undefined.
    interpolation : {'linear', 'lower', 'higher', 'midpoint', 'nearest'}
        This optional parameter specifies the interpolation method to
        use when the desired quantile lies between two data points
        ``i < j``:

            * linear: ``i + (j - i) * fraction``, where ``fraction``
              is the fractional part of the index surrounded by ``i``
              and ``j``.
            * lower: ``i``.
            * higher: ``j``.
            * nearest: ``i`` or ``j``, whichever is nearest.
            * midpoint: ``(i + j) / 2``.
    keepdims : bool, optional
        If this is set to True, the axes which are reduced are left in
        the result as dimensions with size one. With this option, the
        result will broadcast correctly against the original array `a`.

    Returns
    -------
    quantile : scalar or ndarray
        If `q` is a single quantile and `axis=None`, then the result
        is a scalar. If multiple quantiles are given, first axis of
        the result corresponds to the quantiles. The other axes are
        the axes that remain after the reduction of `a`. If the input
        contains integers or floats smaller than ``float64``, the output
        data-type is ``float64``. Otherwise, the output data-type is the
        same as that of the input. If `out` is specified, that array is
        returned instead.

    See Also
    --------
    mean
    percentile : equivalent to quantile, but with q in the range [0, 100].
    median : equivalent to ``quantile(..., 0.5)``
    nanquantile

    Notes
    -----
    Given a vector ``V`` of length ``N``, the q-th quantile of
    ``V`` is the value ``q`` of the way from the minimum to the
    maximum in a sorted copy of ``V``. The values and distances of
    the two nearest neighbors as well as the `interpolation` parameter
    will determine the quantile if the normalized ranking does not
    match the location of ``q`` exactly. This function is the same as
    the median if ``q=0.5``, the same as the minimum if ``q=0.0`` and the
    same as the maximum if ``q=1.0``.

    Examples
    --------
    >>> a = np.array([[10, 7, 4], [3, 2, 1]])
    >>> a
    array([[10,  7,  4],
           [ 3,  2,  1]])
    >>> np.quantile(a, 0.5)
    3.5
    >>> np.quantile(a, 0.5, axis=0)
    array([6.5, 4.5, 2.5])
    >>> np.quantile(a, 0.5, axis=1)
    array([7.,  2.])
    >>> np.quantile(a, 0.5, axis=1, keepdims=True)
    array([[7.],
           [2.]])
    >>> m = np.quantile(a, 0.5, axis=0)
    >>> out = np.zeros_like(m)
    >>> np.quantile(a, 0.5, axis=0, out=out)
    array([6.5, 4.5, 2.5])
    >>> m
    array([6.5, 4.5, 2.5])
    >>> b = a.copy()
    >>> np.quantile(b, 0.5, axis=1, overwrite_input=True)
    array([7.,  2.])
    >>> assert not np.all(a == b)