dask.array.extract

dask.array.extract¶

dask.array.extract(condition, arr)[source]¶

Return the elements of an array that satisfy some condition.

This docstring was copied from numpy.extract.

Some inconsistencies with the Dask version may exist.

This is equivalent to np.compress(ravel(condition), ravel(arr)). If condition is boolean np.extract is equivalent to arr[condition].

Note that place does the exact opposite of extract.

Parameters

conditionarray_like: An array whose nonzero or True entries indicate the elements of arr to extract.
arrarray_like: Input array of the same size as condition.

Returns

extractndarray: Rank 1 array of values from arr where condition is True.

See also

take, put, copyto, compress, place

Examples

>>> arr = np.arange(12).reshape((3, 4))  
>>> arr  
array([[ 0,  1,  2,  3],
       [ 4,  5,  6,  7],
       [ 8,  9, 10, 11]])
>>> condition = np.mod(arr, 3)==0  
>>> condition  
array([[ True, False, False,  True],
       [False, False,  True, False],
       [False,  True, False, False]])
>>> np.extract(condition, arr)  
array([0, 3, 6, 9])

If condition is boolean:

>>> arr[condition]  
array([0, 3, 6, 9])

dask.array.expm1

dask.array.eye