argsort( )函数

>>> import numpy
>>> help(numpy.argsort)
Help on function argsort in module numpy.core.fromnumeric:


argsort(a, axis=-1, kind='quicksort', order=None)
Returns the indices that would sort an array.

Perform an indirect sort along the given axis using the algorithm specified
by the `kind` keyword. It returns an array of indices of the same shape as
`a` that index data along the given axis in sorted order.

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

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

>>> np.argsort(x, axis=0) #按列排序
array([[0, 1],
[1, 0]])

>>> np.argsort(x, axis=1) #按行排序
array([[0, 1],
[0, 1]])

>>> a = x[np.argsort(x)]
>>> a
array([1, 2, 3])
>>> a[::-1]
array([3, 2, 1])