numpy.ndarray.partition¶
method

ndarray.
partition
(kth, axis=1, kind='introselect', order=None)¶ Rearranges the elements in the array in such a way that the value of the element in kth position is in the position it would be in a sorted array. All elements smaller than the kth element are moved before this element and all equal or greater are moved behind it. The ordering of the elements in the two partitions is undefined.
1.8.0 新版功能.
Parameters:  kth : int or sequence of ints
Element index to partition by. The kth element value will be in its final sorted position and all smaller elements will be moved before it and all equal or greater elements behind it. The order of all elements in the partitions is undefined. If provided with a sequence of kth it will partition all elements indexed by kth of them into their sorted position at once.
 axis : int, optional
Axis along which to sort. Default is 1, which means sort along the last axis.
 kind : {‘introselect’}, optional
Selection algorithm. Default is ‘introselect’.
 order : str or list of str, optional
When a is an array with fields defined, this argument specifies which fields to compare first, second, etc. A single field can be specified as a string, and not all fields need to be specified, but unspecified fields will still be used, in the order in which they come up in the dtype, to break ties.
参见
numpy.partition
 Return a parititioned copy of an array.
argpartition
 Indirect partition.
sort
 Full sort.
Notes
See
np.partition
for notes on the different algorithms.Examples
>>> a = np.array([3, 4, 2, 1]) >>> a.partition(3) >>> a array([2, 1, 3, 4])
>>> a.partition((1, 3)) array([1, 2, 3, 4])