numpy.append#

numpy.append(arr,values,axis=None)[source]#

Append values to the end of an array.

Parameters:

arrarray_like

Values are appended to a copy of this array.

valuesarray_like

These values are appended to a copy ofarr. It must be of thecorrect shape (the same shape asarr, excludingaxis). Ifaxis is not specified,values can be any shape and will beflattened before use.

axisint, optional

The axis along whichvalues are appended. Ifaxis is notgiven, botharr andvalues are flattened before use.

Returns:

appendndarray

A copy ofarr withvalues appended toaxis. Note thatappend does not occur in-place: a new array is allocated andfilled. Ifaxis is None,out is a flattened array.

See also

insert

Insert elements into an array.

delete

Delete elements from an array.

Examples

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>>>importnumpyasnp>>>np.append([1,2,3],[[4,5,6],[7,8,9]])array([1, 2, 3, ..., 7, 8, 9])

Whenaxis is specified,values must have the correct shape.

>>>np.append([[1,2,3],[4,5,6]],[[7,8,9]],axis=0)array([[1, 2, 3],       [4, 5, 6],       [7, 8, 9]])

>>>np.append([[1,2,3],[4,5,6]],[7,8,9],axis=0)Traceback (most recent call last):...ValueError:all the input arrays must have same number of dimensions, butthe array at index 0 has 2 dimension(s) and the array at index 1 has 1dimension(s)

>>>a=np.array([1,2],dtype=int)>>>c=np.append(a,[])>>>carray([1., 2.])>>>c.dtypefloat64

Default dtype for empty ndarrays isfloat64 thus making the output of dtypefloat64 when appended with dtypeint64

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