numpy.compress(condition, a, axis=None, out=None)
Return selected slices of an array along given axis.
When working along a given axis, a slice along that axis is returned in output for each index where condition evaluates to True. When working on a 1-D array,
is equivalent to
.
Parameters:condition1-D array of boolsArray that selects which entries to return. If len(condition) is less than the size of a along the given axis, then output is truncated to the length of the condition array.
aarray_likeArray from which to extract a part.
axisint, optionalAxis along which to take slices. If None (default), work on the flattened array.
outndarray, optionalOutput array. Its type is preserved and it must be of the right shape to hold the output.
Returns:compressed_arrayndarrayA copy of a without the slices along axis for which condition is false.
Examples
>>> importnumpyasnp>>> a=np.array([[1,2],[3,4],[5,6]])>>> aarray([[1, 2], [3, 4], [5, 6]])>>> np.compress([0,1],a,axis=0)array([[3, 4]])>>> np.compress([False,True,True],a,axis=0)array([[3, 4], [5, 6]])>>> np.compress([False,True],a,axis=1)array([[2], [4], [6]])Working on the flattened array does not return slices along an axis but selects elements.
>>> np.compress([False,True],a)array([2])