numpy.testing.assert_array_less#

testing.assert_array_less(x, y, err_msg='', verbose=True)[source]#

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 x is not strictly smaller than y, element-wise.

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])