max¶

max(a, axis=None, out=None, keepdims=False)¶

Return the maximum of an array or maximum along an axis.

Parameters:

a : ndarray: Input data.
axis : int, optional: Axis along which to operate. By default, flattened input is used.
out : ndarray, optional: Alternative output array in which to place the result. Must be of the same shape and buffer length as the expected output. See doc.ufuncs (Section “Output arguments”) for more details.
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 arr.

Returns:

max : ndarray: Maximum of a. If axis is None, the result is an array of dimension 1. If axis is given, the result is an array of dimension a.ndim - 1.

See also

min: The minimum value of an array along a given axis, ignoring any nan.
maximum: Element-wise maximum of two arrays, ignoring any nan.
argmax: Return the indices of the maximum values.

Notes

NaN in the orginal numpy is denoted as nan and will be ignored.

Don’t use max for element-wise comparison of 2 arrays; when a.shape[0] is 2, maximum(a[0], a[1]) is faster than max(a, axis=0).

Examples

>>> a = np.arange(4).reshape((2,2))
>>> a
array([[0., 1.],
    [2., 3.]]) 
>>> np.max(a)            # Maximum of the flattened array
array(3.)
>>> np.max(a, axis=0)    # Maxima along the first axis
array([2., 3.])
>>> np.max(a, axis=1)    # Maxima along the second axis
array([1., 3.])

>>> b = np.arange(5, dtype=np.float32)
>>> b[2] = np.nan
>>> np.max(b)
array(4.)