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# numpy.extract

`numpy.``extract`(condition, arr)

  Return the elements of an array that satisfy some condition.

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

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

  See also

  `take`, `put`, `putmask`

  Examples

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

  If condition is boolean:

      >>> arr[condition]
      array([ 3,  6,  9, 12])

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