numpy.testing.assert_array_less

numpy.testing.assert_array_less(x, y, err_msg='', verbose=True)

Raises an AssertionError if two array_like objects are not ordered by less than.

Given two array_like objects, check that the shape is equal and all elements of the first object are strictly smaller than those of the second object. An exception is raised at shape mismatch or incorrectly ordered values. Shape mismatch does not raise if an object has zero dimension. In contrast to the standard usage in numpy, NaNs are compared, no assertion is raised if both objects have NaNs in the same positions.

Parameters

xarray_like

The smaller object to check.

yarray_like

The larger object to compare.

err_msgstring

The error message to be printed in case of failure.

verbosebool

If True, the conflicting values are appended to the error message.

Raises

AssertionError

If actual and desired objects are not equal.

See also

assert_array_equal

tests objects for equality

assert_array_almost_equal

test objects for equality up to precision

Examples

>>> np.testing.assert_array_less([1.0, 1.0, np.nan], [1.1, 2.0, np.nan])
>>> np.testing.assert_array_less([1.0, 1.0, np.nan], [1, 2.0, np.nan])
Traceback (most recent call last):
    ...
AssertionError:
Arrays are not less-ordered

Mismatched elements: 1 / 3 (33.3%)
Max absolute difference: 1.
Max relative difference: 0.5
 x: array([ 1.,  1., nan])
 y: array([ 1.,  2., nan])

>>> np.testing.assert_array_less([1.0, 4.0], 3)
Traceback (most recent call last):
    ...
AssertionError:
Arrays are not less-ordered

Mismatched elements: 1 / 2 (50%)
Max absolute difference: 2.
Max relative difference: 0.66666667
 x: array([1., 4.])
 y: array(3)

>>> np.testing.assert_array_less([1.0, 2.0, 3.0], [4])
Traceback (most recent call last):
    ...
AssertionError:
Arrays are not less-ordered

(shapes (3,), (1,) mismatch)
 x: array([1., 2., 3.])
 y: array([4])