numpy.ma.MaskedArray.compress¶

MaskedArray.compress(condition,axis=None,out=None)[source]¶

Returna where condition isTrue.

If condition is aMaskedArray, missing values are consideredasFalse.

Parameters:

condition : var Boolean 1-d array selecting which entries to return. If len(condition)is less than the size of a along the axis, then output is truncatedto length of condition array. axis : {None, int}, optional Axis along which the operation must be performed. out : {None, ndarray}, optional Alternative output array in which to place the result. It must havethe same shape as the expected output but the type will be cast ifnecessary.

Returns:

result : MaskedArray AMaskedArray object.

Notes

Please note the difference withcompressed !The output ofcompress has a mask, the output ofcompressed does not.

Examples

>>>x=np.ma.array([[1,2,3],[4,5,6],[7,8,9]],mask=[0]+[1,0]*4)>>>print(x)[[1 -- 3] [-- 5 --] [7 -- 9]]>>>x.compress([1,0,1])masked_array(data = [1 3],      mask = [False False],      fill_value=999999)

>>>x.compress([1,0,1],axis=1)masked_array(data = [[1 3] [-- --] [7 9]],      mask = [[False False] [ True  True] [False False]],      fill_value=999999)