MAINT: Chain some exceptions in arraysetops. (#17132)

* MAINT: chain type error line 303 arraysetops.py

* MAINT: chain axis error line 281 arraysetops.py

* Revert "MAINT: chain axis error line 281 arraysetops.py"

This reverts commit f6e1f544bebb7e5346cb83bdac9756be6ee9f4f6.

* MAINT: chain axis error line 281 arraysetops.py to be from None

1 files changed, 3 insertions, 3 deletions

diff --git a/numpy/lib/arraysetops.py b/numpy/lib/arraysetops.py
index df9a110c5..6a2ad004c 100644
--- a/numpy/lib/arraysetops.py
+++ b/numpy/lib/arraysetops.py
@@ -278,7 +278,7 @@ def unique(ar, return_index=False, return_inverse=False,
         ar = np.moveaxis(ar, axis, 0)
     except np.AxisError:
         # this removes the "axis1" or "axis2" prefix from the error message
-        raise np.AxisError(axis, ar.ndim)
+        raise np.AxisError(axis, ar.ndim) from None
 
     # Must reshape to a contiguous 2D array for this to work...
     orig_shape, orig_dtype = ar.shape, ar.dtype
@@ -300,10 +300,10 @@ def unique(ar, return_index=False, return_inverse=False,
             # array with shape `(len(ar),)`.  Because `dtype` in this case has
             # itemsize 0, the total size of the result is still 0 bytes.
             consolidated = np.empty(len(ar), dtype=dtype)
-    except TypeError:
+    except TypeError as e:
         # There's no good way to do this for object arrays, etc...
         msg = 'The axis argument to unique is not supported for dtype {dt}'
-        raise TypeError(msg.format(dt=ar.dtype))
+        raise TypeError(msg.format(dt=ar.dtype)) from e
 
     def reshape_uniq(uniq):
         n = len(uniq)