Fix "The truth value of an array with more than one element is ambiguous" (#1685)

* Fix "The truth value of an array with more than one element is ambiguous". Fixes "ValueError: The truth value of an array with more than one element is ambiguous. Use a.any() or a.all()"

Author: MrQubo

Diff for: packages/python/plotly/plotly/subplots.py

@@ -511,13 +511,13 @@ def _checks(item, defaults):
 
     # ### vertical_spacing ###
     if vertical_spacing is None:
-        if subplot_titles:
+        if subplot_titles is not None:
             vertical_spacing = 0.5 / rows
         else:
             vertical_spacing = 0.3 / rows
 
     # ### subplot titles ###
-    if not subplot_titles:
+    if subplot_titles is None:
         subplot_titles = [""] * rows * cols
 
     # ### column_widths ###

Diff for: packages/python/plotly/plotly/tests/test_core/test_subplots/test_make_subplots.py

@@ -1542,6 +1542,24 @@ def test_subplot_titles_insets(self):
         )
         self.assertEqual(fig, expected)
 
+    def test_subplot_titles_array(self):
+        # Pass python array
+        expected = tls.make_subplots(
+            insets=[{"cell": (1, 1), "l": 0.7, "b": 0.3}], subplot_titles=("", "Inset")
+        )
+        fig = tls.make_subplots(
+            insets=[{"cell": (1, 1), "l": 0.7, "b": 0.3}], subplot_titles=["", "Inset"]
+        )
+        self.assertEqual(fig, expected)
+
+    def test_subplot_titles_empty(self):
+        # Pass empty array
+        expected = tls.make_subplots(insets=[{"cell": (1, 1), "l": 0.7, "b": 0.3}])
+        fig = tls.make_subplots(
+            insets=[{"cell": (1, 1), "l": 0.7, "b": 0.3}], subplot_titles=[]
+        )
+        self.assertEqual(fig, expected)
+
     def test_large_columns_no_errors(self):
         """
         Test that creating subplots with a large number of columns, and

Diff for: packages/python/plotly/plotly/tests/test_optional/test_subplots/test_make_subplots.py

@@ -0,0 +1,18 @@
+import numpy as np
+
+from unittest import TestCase
+
+import plotly.tools as tls
+
+
+class TestMakeSubplots(TestCase):
+    def test_subplot_titles_numpy_array(self):
+        # Pass numpy array
+        expected = tls.make_subplots(
+            insets=[{"cell": (1, 1), "l": 0.7, "b": 0.3}], subplot_titles=("", "Inset")
+        )
+        fig = tls.make_subplots(
+            insets=[{"cell": (1, 1), "l": 0.7, "b": 0.3}],
+            subplot_titles=np.array(["", "Inset"]),
+        )
+        self.assertEqual(fig, expected)