numpy.ma.choose()

numpy.ma.choose(indices, choices, out=None, mode='raise') [source]

Use an index array to construct a new array from a set of choices.

Given an array of integers and a set of n choice arrays, this method will create a new array that merges each of the choice arrays. Where a value in a is i, the new array will have the value that choices[i] contains in the same place.

Parameters:

Parameters:	a : ndarray of ints This array must contain integers in `[0, n-1]`, where n is the number of choices. choices : sequence of arrays Choice arrays. The index array and all of the choices should be broadcastable to the same shape. out : array, optional If provided, the result will be inserted into this array. It should be of the appropriate shape and `dtype`. mode : {?raise?, ?wrap?, ?clip?}, optional Specifies how out-of-bounds indices will behave. ?raise? : raise an error ?wrap? : wrap around ?clip? : clip to the range
Returns:	merged_array : array

a : ndarray of ints

This array must contain integers in [0, n-1], where n is the number of choices.

choices : sequence of arrays

Choice arrays. The index array and all of the choices should be broadcastable to the same shape.

out : array, optional

If provided, the result will be inserted into this array. It should be of the appropriate shape and dtype.

mode : {?raise?, ?wrap?, ?clip?}, optional

Specifies how out-of-bounds indices will behave.

?raise? : raise an error
?wrap? : wrap around
?clip? : clip to the range

Returns:

merged_array : array

Examples

>>> choice = np.array([[1,1,1], [2,2,2], [3,3,3]])
>>> a = np.array([2, 1, 0])
>>> np.ma.choose(a, choice)
masked_array(data = [3 2 1],
      mask = False,
      fill_value=999999)

Links:

https://docs.scipy.org/doc/numpy-1.11.0/reference/generated/numpy.ma.choose.html

doc_NumPy

2017-01-10 18:15:05

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