Close streamlit#1092 (streamlit#1270)

Author: kantuni

examples/core/slider.py

@@ -15,8 +15,8 @@
 
 import streamlit as st
 
-w1 = st.slider('Label 1', 25, 0, 100, 1)
+w1 = st.slider('Label 1', 0, 100, 25, 1)
 st.write('Value 1:', w1)
 
-w2 = st.slider('Label 2', (25.0, 75.0), 0.0, 100.0, 0.5)
+w2 = st.slider('Label 2', 0.0, 100.0, (25.0, 75.0), 0.5)
 st.write('Value 2:', w2)

lib/streamlit/DeltaGenerator.py

@@ -1372,24 +1372,24 @@ def selectbox(self, element, ui_value, label, options, index=0,
         return options[current_value] if len(options) else NoValue
 
     @_widget
-    def slider(self, element, ui_value, label, value=None,
-               min_value=None, max_value=None, step=None):
+    def slider(self, element, ui_value, label,
+               min_value=None, max_value=None, value=None, step=None):
         """Display a slider widget.
 
         Parameters
         ----------
         label : str
             A short label explaining to the user what this slider is for.
-        value : int/float or a tuple/list of int/float
-            The value of this widget when it first renders. In case the value
-            is passed as a tuple/list a range slider will be used.
-            Defaults to 0.
         min_value : int/float
             The minimum permitted value.
             Defaults to 0 if the value is an int, 0.0 otherwise.
         max_value : int/float
             The maximum permitted value.
             Defaults 100 if the value is an int, 1.0 otherwise.
+        value : int/float or a tuple/list of int/float
+            The value of this widget when it first renders. In case the value
+            is passed as a tuple/list a range slider will be used.
+            Defaults to min_value.
         step : int/float
             The stepping interval.
             Defaults to 1 if the value is an int, 0.01 otherwise.
@@ -1413,7 +1413,7 @@ def slider(self, element, ui_value, label, value=None,
         """
         # Set value default.
         if value is None:
-            value = 0
+            value = min_value if min_value is not None else 0
 
         # Ensure that the value is either a single value or a range of values.
         single_value = isinstance(value, (int, float))

lib/tests/streamlit/slider_test.py

@@ -42,7 +42,7 @@ def test_just_label(self):
     ])
     def test_value_types(self, arg_value, proto_value, return_value):
         """Test that it supports different types of values."""
-        ret = st.slider('the label', arg_value)
+        ret = st.slider('the label', value=arg_value)
 
         self.assertEqual(ret, return_value)
 
@@ -52,22 +52,22 @@ def test_value_types(self, arg_value, proto_value, return_value):
 
     def test_value_greater_than_min(self):
         with pytest.raises(ValueError) as exc_slider:
-            st.slider('Slider label', 0, 10, 100)
+            st.slider('Slider label', 10, 100, 0)
         assert ('The default `value` of 0 must lie between the `min_value` of '
                 '10 and the `max_value` of 100, inclusively.'
                 == str(exc_slider.value))
 
     def test_value_smaller_than_max(self):
         with pytest.raises(ValueError) as exc_slider:
-            st.slider('Slider label', 101, 10, 100)
+            st.slider('Slider label', 10, 100, 101)
         assert ('The default `value` of 101 '
                 'must lie between the `min_value` of 10 '
                 'and the `max_value` of 100, inclusively.'
                 == str(exc_slider.value))
 
     def test_max_min(self):
         with pytest.raises(ValueError) as exc_slider:
-            st.slider('Slider label', 101, 101, 100)
+            st.slider('Slider label', 101, 100, 101)
         assert ('The default `value` of 101 '
                 'must lie between the `min_value` of 101 '
                 'and the `max_value` of 100, inclusively.'