numpy.ma.masked_array.compress¶
method

masked_array.
compress
(condition, axis=None, out=None)[源代码]¶ Return a where condition is
True
.If condition is a
MaskedArray
, missing values are considered asFalse
.Parameters:  condition : var
Boolean 1d array selecting which entries to return. If len(condition) is less than the size of a along the axis, then output is truncated to 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 have the same shape as the expected output but the type will be cast if necessary.
Returns:  result : MaskedArray
A
MaskedArray
object.
Notes
Please note the difference with
compressed
! 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)