docs: Use when in arguments syntax examples (2/2)

tests/examples_arguments_syntax/bar_chart_with_highlighted_bar.py

@@ -9,13 +9,15 @@
 
 source = data.wheat()
 
-alt.Chart(source).mark_bar().encode(
-    x='year:O',
-    y="wheat:Q",
-    # The highlight will be set on the result of a conditional statement
-    color=alt.condition(
-        alt.datum.year == 1810,  # If the year is 1810 this test returns True,
-        alt.value('orange'),     # which sets the bar orange.
-        alt.value('steelblue')   # And if it's not true it sets the bar steelblue.
-    )
-).properties(width=600)
+# If the `year` column equals `1810`
+# then, set the bar color to `"orange"`
+# otherwise, use `"steelblue"`
+color = alt.when(year=1810).then(alt.value("orange")).otherwise(alt.value("steelblue"))
+
+chart = (
+    alt.Chart(source)
+    .mark_bar()
+    .encode(x="year:O", y="wheat:Q", color=color)
+    .properties(width=600)
+)
+chart

tests/examples_arguments_syntax/bar_chart_with_negatives.py

@@ -9,12 +9,13 @@
 
 source = data.us_employment()
 
-alt.Chart(source).mark_bar().encode(
-    x="month:T",
-    y="nonfarm_change:Q",
-    color=alt.condition(
-        alt.datum.nonfarm_change > 0,
-        alt.value("steelblue"),  # The positive color
-        alt.value("orange")  # The negative color
-    )
-).properties(width=600)
+predicate = alt.datum.nonfarm_change > 0
+color = alt.when(predicate).then(alt.value("steelblue")).otherwise(alt.value("orange"))
+
+chart = (
+    alt.Chart(source)
+    .mark_bar()
+    .encode(x="month:T", y="nonfarm_change:Q", color=color)
+    .properties(width=600)
+)
+chart

tests/examples_arguments_syntax/candlestick_chart.py

@@ -12,9 +12,11 @@
 
 source = data.ohlc()
 
-open_close_color = alt.condition("datum.open <= datum.close",
-                                 alt.value("#06982d"),
-                                 alt.value("#ae1325"))
+open_close_color = (
+    alt.when("datum.open <= datum.close")
+    .then(alt.value("#06982d"))
+    .otherwise(alt.value("#ae1325"))
+)
 
 base = alt.Chart(source).encode(
     alt.X('date:T',

tests/examples_arguments_syntax/dot_dash_plot.py

@@ -12,28 +12,30 @@
 
 # Configure the options common to all layers
 brush = alt.selection_interval()
+brush_origin = alt.when(brush).then("Origin")
 base = alt.Chart(source).add_params(brush)
 
 # Configure the points
 points = base.mark_point().encode(
     x=alt.X('Miles_per_Gallon', title=''),
     y=alt.Y('Horsepower', title=''),
-    color=alt.condition(brush, 'Origin', alt.value('grey'))
+    color=brush_origin.otherwise(alt.value("grey")),
 )
 
 # Configure the ticks
 tick_axis = alt.Axis(labels=False, domain=False, ticks=False)
+tick_color = brush_origin.otherwise(alt.value("lightgrey"))
 
 x_ticks = base.mark_tick().encode(
     alt.X('Miles_per_Gallon', axis=tick_axis),
     alt.Y('Origin', title='', axis=tick_axis),
-    color=alt.condition(brush, 'Origin', alt.value('lightgrey'))
+    color=tick_color
 )
 
 y_ticks = base.mark_tick().encode(
     alt.X('Origin', title='', axis=tick_axis),
     alt.Y('Horsepower', axis=tick_axis),
-    color=alt.condition(brush, 'Origin', alt.value('lightgrey'))
+    color=tick_color
 )
 
 # Build the chart

tests/examples_arguments_syntax/interactive_brush.py

@@ -15,5 +15,5 @@
 alt.Chart(source).mark_point().encode(
     x='Horsepower:Q',
     y='Miles_per_Gallon:Q',
-    color=alt.condition(brush, 'Cylinders:O', alt.value('grey')),
+    color=alt.when(brush).then("Cylinders:O").otherwise(alt.value("grey")),
 ).add_params(brush)

tests/examples_arguments_syntax/interactive_reorder_stacked_bars.py

@@ -25,7 +25,7 @@
     y='variety:N',
     color='site:N',
     order='site_order:N',
-    opacity=alt.condition(selection, alt.value(0.9), alt.value(0.2))
+    opacity=alt.when(selection).then(alt.value(0.9)).otherwise(alt.value(0.2))
 ).add_params(
     selection
 )

tests/examples_arguments_syntax/scatter_linked_brush.py

@@ -14,7 +14,7 @@
 
 base = alt.Chart(source).mark_point().encode(
     y='Miles_per_Gallon',
-    color=alt.condition(brush, 'Origin', alt.ColorValue('gray')),
+    color=alt.when(brush).then("Origin").otherwise(alt.ColorValue("gray")),
 ).add_params(
     brush
 ).properties(

tests/examples_arguments_syntax/scatter_with_histogram.py

@@ -42,7 +42,7 @@
 mag = alt.Chart().mark_bar().encode(
     x='mbin:N',
     y="count()",
-    color=alt.condition(pts, alt.value("black"), alt.value("lightgray"))
+    color=alt.when(pts).then(alt.value("black")).otherwise(alt.value("lightgray"))
 ).properties(
     width=300,
     height=300

tests/examples_arguments_syntax/selection_histogram.py

@@ -16,7 +16,7 @@
 points = alt.Chart(source).mark_point().encode(
     x='Horsepower:Q',
     y='Miles_per_Gallon:Q',
-    color=alt.condition(brush, 'Origin:N', alt.value('lightgray'))
+    color=alt.when(brush).then("Origin:N").otherwise(alt.value("lightgray"))
 ).add_params(
     brush
 )

tests/examples_arguments_syntax/selection_layer_bar_month.py

@@ -15,7 +15,7 @@
 bars = alt.Chart().mark_bar().encode(
     x='month(date):O',
     y='mean(precipitation):Q',
-    opacity=alt.condition(brush, alt.OpacityValue(1), alt.OpacityValue(0.7)),
+    opacity = alt.when(brush).then(alt.value(1)).otherwise(alt.value(0.7)),
 ).add_params(
     brush
 )

tests/examples_arguments_syntax/selection_zorder.py

@@ -16,18 +16,19 @@
 cars = data.cars.url
 
 hover = alt.selection_point(on='pointerover', nearest=True, empty=False)
+when_hover = alt.when(hover)
 
 chart = alt.Chart(cars, title='Selection obscured by other points').mark_circle(opacity=1).encode(
     x='Horsepower:Q',
     y='Miles_per_Gallon:Q',
-    color=alt.condition(hover, alt.value('coral'), alt.value('lightgray')),
-    size=alt.condition(hover, alt.value(300), alt.value(30))
+    color=when_hover.then(alt.value("coral")).otherwise(alt.value("lightgray")),
+    size=when_hover.then(alt.value(300)).otherwise(alt.value(30))
 ).add_params(
     hover
 )
 
 chart | chart.encode(
-    order=alt.condition(hover, alt.value(1), alt.value(0))
+    order=when_hover.then(alt.value(1)).otherwise(alt.value(0))
 ).properties(
     title='Selection brought to front'
 )

tests/examples_arguments_syntax/slider_cutoff.py

@@ -17,14 +17,12 @@
 
 slider = alt.binding_range(min=0, max=100, step=1)
 cutoff = alt.param(bind=slider, value=50)
+predicate = alt.datum.xval < cutoff
 
 alt.Chart(df).mark_point().encode(
     x='xval',
     y='yval',
-    color=alt.condition(
-        alt.datum.xval < cutoff,
-        alt.value('red'), alt.value('blue')
-    )
+    color=alt.when(predicate).then(alt.value("red")).otherwise(alt.value("blue")),
 ).add_params(
     cutoff
 )