numpy.transpose#
- numpy.transpose(a,axes=None)[source]#
Returns an array with axes transposed.
For a 1-D array, this returns an unchanged view of the original array, as atransposed vector is simply the same vector.To convert a 1-D array into a 2-D column vector, an additional dimensionmust be added, e.g.,
np.atleast_2d(a).T
achieves this, as doesa[:,np.newaxis]
.For a 2-D array, this is the standard matrix transpose.For an n-D array, if axes are given, their order indicates how theaxes are permuted (see Examples). If axes are not provided, thentranspose(a).shape==a.shape[::-1]
.- Parameters:
- aarray_like
Input array.
- axestuple or list of ints, optional
If specified, it must be a tuple or list which contains a permutationof [0, 1, …, N-1] where N is the number of axes ofa. Negativeindices can also be used to specify axes. The i-th axis of the returnedarray will correspond to the axis numbered
axes[i]
of the input.If not specified, defaults torange(a.ndim)[::-1]
, which reversesthe order of the axes.
- Returns:
- pndarray
a with its axes permuted. A view is returned whenever possible.
See also
ndarray.transpose
Equivalent method.
moveaxis
Move axes of an array to new positions.
argsort
Return the indices that would sort an array.
Notes
Use
transpose(a,argsort(axes))
to invert the transposition of tensorswhen using theaxes keyword argument.Examples
>>>importnumpyasnp>>>a=np.array([[1,2],[3,4]])>>>aarray([[1, 2], [3, 4]])>>>np.transpose(a)array([[1, 3], [2, 4]])
>>>a=np.array([1,2,3,4])>>>aarray([1, 2, 3, 4])>>>np.transpose(a)array([1, 2, 3, 4])
>>>a=np.ones((1,2,3))>>>np.transpose(a,(1,0,2)).shape(2, 1, 3)
>>>a=np.ones((2,3,4,5))>>>np.transpose(a).shape(5, 4, 3, 2)
>>>a=np.arange(3*4*5).reshape((3,4,5))>>>np.transpose(a,(-1,0,-2)).shape(5, 3, 4)