MAINT: Do not emit empty Methods heading in np.info (#17498)

Fixes the incompatible type comparison found in #17490.

This also corrects the logic to not print the heading when only private/magic methods are present.

numpy/lib/tests/test_utils.py

@@ -140,3 +140,22 @@ def test_strided(self):
 def test_assert_raises_regex_context_manager():
     with assert_raises_regex(ValueError, 'no deprecation warning'):
         raise ValueError('no deprecation warning')
+
+
+def test_info_method_heading():
+    # info(class) should only print "Methods:" heading if methods exist
+
+    class NoPublicMethods:
+        pass
+
+    class WithPublicMethods:
+        def first_method():
+            pass
+
+    def _has_method_heading(cls):
+        out = StringIO()
+        utils.info(cls, output=out)
+        return 'Methods:' in out.getvalue()
+
+    assert _has_method_heading(WithPublicMethods)
+    assert not _has_method_heading(NoPublicMethods)

numpy/lib/utils.py

@@ -587,11 +587,11 @@ def info(object=None, maxwidth=76, output=sys.stdout, toplevel='numpy'):
             print(inspect.getdoc(object), file=output)
 
         methods = pydoc.allmethods(object)
-        if methods != []:
+
+        public_methods = [meth for meth in methods if meth[0] != '_']
+        if public_methods:
             print("\n\nMethods:\n", file=output)
-            for meth in methods:
-                if meth[0] == '_':
-                    continue
+            for meth in public_methods:
                 thisobj = getattr(object, meth, None)
                 if thisobj is not None:
                     methstr, other = pydoc.splitdoc(