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# numpy.testing.assert_array_equal

testing.assert_array_equal(actual, desired, err_msg='', verbose=True, *, strict=False)

  Raises an AssertionError if two array_like objects are not equal.

  Given two array_like objects, check that the shape is equal and all elements of these objects are equal (but see the Notes for the special handling of a scalar). An exception is raised at shape mismatch or conflicting values. In contrast to the standard usage in numpy, NaNs are compared like numbers, no assertion is raised if both objects have NaNs in the same positions.

  The usual caution for verifying equality with floating point numbers is advised.

  Note

  When either actual or desired is already an instance of `numpy.ndarray` and desired is not a `dict`, the behavior of `assert_equal(actual, desired)` is identical to the behavior of this function. Otherwise, this function performs np.asanyarray on the inputs before comparison, whereas `assert_equal` defines special comparison rules for common Python types. For example, only `assert_equal` can be used to compare nested Python lists. In new code, consider using only `assert_equal`, explicitly converting either actual or desired to arrays if the behavior of `assert_array_equal` is desired.

  Parameters:
    actual array_like

      The actual object to check.

    desired array_like

      The desired, expected object.

    err_msg str, optional

      The error message to be printed in case of failure.

    verbose bool, optional

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

    strict bool, optional

      If True, raise an AssertionError when either the shape or the data type of the array_like objects does not match. The special handling for scalars mentioned in the Notes section is disabled.

      New in version 1.24.0.

  Raises:
    AssertionError

      If actual and desired objects are not equal.

  See also

  `assert_allclose`

    Compare two array_like objects for equality with desired relative and/or absolute precision.

  `assert_array_almost_equal_nulp`, `assert_array_max_ulp`, `assert_equal`

  Notes

  When one of actual and desired is a scalar and the other is array_like, the function checks that each element of the array_like is equal to the scalar. Note that empty arrays are therefore considered equal to scalars. This behaviour can be disabled by setting `strict==True`.

  Examples

  The first assert does not raise an exception:

      >>> np.testing.assert_array_equal([1.0,2.33333,np.nan],
      ...                               [np.exp(0),2.33333, np.nan])

  Assert fails with numerical imprecision with floats:

      >>> np.testing.assert_array_equal([1.0,np.pi,np.nan],
      ...                               [1, np.sqrt(np.pi)**2, np.nan])
      Traceback (most recent call last):
          ...
      AssertionError:
      Arrays are not equal

      Mismatched elements: 1 / 3 (33.3%)
      Mismatch at index:
       [1]: 3.141592653589793 (ACTUAL), 3.1415926535897927 (DESIRED)
      Max absolute difference among violations: 4.4408921e-16
      Max relative difference among violations: 1.41357986e-16
       ACTUAL: array([1.      , 3.141593,      nan])
       DESIRED: array([1.      , 3.141593,      nan])

  Use `assert_allclose` or one of the nulp (number of floating point values) functions for these cases instead:

      >>> np.testing.assert_allclose([1.0,np.pi,np.nan],
      ...                            [1, np.sqrt(np.pi)**2, np.nan],
      ...                            rtol=1e-10, atol=0)

  As mentioned in the Notes section, `assert_array_equal` has special handling for scalars. Here the test checks that each value in x is 3:

      >>> x = np.full((2, 5), fill_value=3)
      >>> np.testing.assert_array_equal(x, 3)

  Use strict to raise an AssertionError when comparing a scalar with an array:

      >>> np.testing.assert_array_equal(x, 3, strict=True)
      Traceback (most recent call last):
          ...
      AssertionError:
      Arrays are not equal

      (shapes (2, 5), () mismatch)
       ACTUAL: array([[3, 3, 3, 3, 3],
             [3, 3, 3, 3, 3]])
       DESIRED: array(3)

  The strict parameter also ensures that the array data types match:

      >>> x = np.array([2, 2, 2])
      >>> y = np.array([2., 2., 2.], dtype=np.float32)
      >>> np.testing.assert_array_equal(x, y, strict=True)
      Traceback (most recent call last):
          ...
      AssertionError:
      Arrays are not equal

      (dtypes int64, float32 mismatch)
       ACTUAL: array([2, 2, 2])
       DESIRED: array([2., 2., 2.], dtype=float32)