numpy.argsort的用法介绍

参考文章：https://docs.scipy.org/doc/numpy-1.13.0/reference/generated/numpy.argsort.html

numpy. argsort ( a,  axis=-1,  kind='quicksort',  order=None )

返回数组排序后对应的下标。kind是排序算法，axis是排序的轴。

Parameters:

a : array_like Array to sort. axis : int or None, optional Axis along which to sort. The default is -1 (the last axis). If None, the flattened array is used. kind : {‘quicksort’, ‘mergesort’, ‘heapsort’}, optional Sorting algorithm. 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 be specified, but unspecified fields will still be used, in the order in which they come up in the dtype, to break ties.

Returns:

index_array : ndarray, int Array of indices that sort a along the specified axis. If a is one-dimensional, a[index_array]yields a sorted a.

举例：

1、一维数组

>>> x = np.array([3, 1, 2])
>>> np.argsort(x)
array([1, 2, 0])

2、二维数组

>>> x = np.array([[0, 3], [2, 2]])
>>> x
array([[0, 3],
       [2, 2]])

>>> np.argsort(x, axis=0)
array([[0, 1],
       [1, 0]])

>>> np.argsort(x, axis=1)
array([[0, 1],
       [0, 1]])