numpy.delete#

numpy.delete(arr,obj,axis=None)[source]#

Return a new array with sub-arrays along an axis deleted. For a onedimensional array, this returns those entries not returned byarr[obj].

Parameters:
arrarray_like

Input array.

objslice, int, array-like of ints or bools

Indicate indices of sub-arrays to remove along the specified axis.

Changed in version 1.19.0:Boolean indices are now treated as a mask of elements to remove,rather than being cast to the integers 0 and 1.

axisint, optional

The axis along which to delete the subarray defined byobj.Ifaxis is None,obj is applied to the flattened array.

Returns:
outndarray

A copy ofarr with the elements specified byobj removed. Notethatdelete does not occur in-place. Ifaxis is None,out isa flattened array.

See also

insert

Insert elements into an array.

append

Append elements at the end of an array.

Notes

Often it is preferable to use a boolean mask. For example:

>>>arr=np.arange(12)+1>>>mask=np.ones(len(arr),dtype=bool)>>>mask[[0,2,4]]=False>>>result=arr[mask,...]

Is equivalent tonp.delete(arr,[0,2,4],axis=0), but allows furtheruse ofmask.

Examples

>>>importnumpyasnp>>>arr=np.array([[1,2,3,4],[5,6,7,8],[9,10,11,12]])>>>arrarray([[ 1,  2,  3,  4],       [ 5,  6,  7,  8],       [ 9, 10, 11, 12]])>>>np.delete(arr,1,0)array([[ 1,  2,  3,  4],       [ 9, 10, 11, 12]])
>>>np.delete(arr,np.s_[::2],1)array([[ 2,  4],       [ 6,  8],       [10, 12]])>>>np.delete(arr,[1,3,5],None)array([ 1,  3,  5,  7,  8,  9, 10, 11, 12])
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