Add some examples

altair/examples/cyperpunk_style_plot.py

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+"""
+Cyberpunk Style Plot
+--------------------
+Inspired by `this chart <https://towardsdatascience.com/cyberpunk-style-with-matplotlib-f47404c9d4c5>`_ by `@d_haitz <https://twitter.com/d_haitz>`_. This example shows how to layer line plots of varying size to create a neon glow effect.
+"""
+# category: case studies
+import altair as alt
+import pandas as pd
+
+df = pd.DataFrame({'A': [1, 3, 9, 5, 2, 1, 1],
+                   'B': [4, 5, 5, 7, 9, 8, 6]})
+
+base = alt.Chart(
+    df.reset_index().melt(id_vars='index')
+).encode(
+    x=alt.X('index:Q'),
+    y=alt.Y('value:Q'),
+    color=alt.Color('variable:N',
+                    scale=alt.Scale(range=['#08F7FE', '#FE53BB']))
+)
+
+# draw lines and circles
+chart = base.mark_circle(size=100, opacity=1)
+chart += base.mark_line(size=2.5)
+
+# make it glow
+n_lines = 10
+diff_linewidth = 1.25
+alpha_value = 0.3 / n_lines
+
+for n in range(n_lines):
+    line_width = 5 + (diff_linewidth * n)
+    chart += base.mark_line(opacity=alpha_value,
+                            size=line_width)
+
+# fill area underneath lines
+chart += base.mark_area(opacity=0.1)
+
+chart.configure_axis(
+    title=None,
+    ticks=False,
+    domain=False,
+    gridColor='#2A3459',
+    labelColor='#D3D3D3',
+    labelFontSize=14,
+    labelPadding=10,
+    labelSeparation=40
+).configure_legend(
+    title=None,
+    labelColor='#D3D3D3',
+    labelFontSize=14,
+    orient='top-right',
+    symbolType='stroke',
+    symbolStrokeWidth=3,
+    symbolSize=600
+).configure_view(
+    strokeWidth=0
+).properties(
+    background='#212946',
+    width=600,
+    height=350
+)

altair/examples/faceted_bullet_chart.py

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+"""
+Faceted Bullet Chart
+--------------------
+This example shows how to facet and layer bar charts to create a bullet chart.
+"""
+# category: other charts
+import altair as alt
+
+source = {'values': [
+    {'title': 'Revenue', 'subtitle': 'US$, in thousands',
+     'ranges': [150, 225, 300], 'measures': [220, 270], 'markers': [250]
+     },
+    {'title': 'Profit', 'subtitle': '%',
+     'ranges': [20, 25, 30], 'measures': [21, 23], 'markers': [26]
+     },
+    {'title': 'Order Size', 'subtitle': 'US$, average',
+     'ranges': [350, 500, 600], 'measures': [100, 320], 'markers': [550]
+     },
+    {'title': 'New Customers', 'subtitle': 'count',
+     'ranges': [1400, 2000, 2500], 'measures': [1000, 1650], 'markers': [2100]
+     },
+    {'title': 'Satisfaction', 'subtitle': 'out of 5',
+     'ranges': [3.5, 4.25, 5], 'measures': [3.2, 4.7], 'markers': [4.4]
+     }
+]}
+
+base = alt.Chart(source)
+
+chart = base.mark_bar(
+).encode(
+    x=alt.X('ranges[2]:Q', scale=alt.Scale(nice=False)),
+    color=alt.value('#eee')
+)
+
+chart += base.mark_bar(
+).encode(
+    x='ranges[1]:Q',
+    color=alt.value('#ddd')
+)
+
+chart += base.mark_bar(
+).encode(
+    x='ranges[0]:Q',
+    color=alt.value('#ccc')
+)
+
+chart += base.mark_bar(
+).encode(
+    x='measures[1]:Q',
+    color=alt.value('lightsteelblue'),
+    size=alt.value(10),
+    opacity=alt.value(1)
+)
+
+chart += base.mark_bar(
+).encode(
+    x='measures[0]:Q',
+    color=alt.value('steelblue'),
+    size=alt.value(10)
+)
+
+chart += base.mark_tick(
+).encode(
+    x='markers[0]:Q',
+    color=alt.value('black')
+)
+
+chart.facet(
+    row=alt.Row('title:N', title=None,
+                header=alt.Header(labelAngle=0, labelAlign='left', title=None))
+).resolve_scale(
+    x='independent'
+).configure_facet(
+    spacing=10
+).configure_axis(
+    title=None
+).configure_tick(
+    thickness=2
+)

altair/examples/weekly_weather_plot.py

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+"""
+Weekly Weather Plot
+-------------------
+Inspired by this `Vega-Lite example <https://vega.github.io/vega-lite/examples/bar_layered_weather.html>`_ by `@melissatdiamond <https://github.com/melissatdiamond>`_. This example shows how to layer bar charts to plot weekly weather data.
+"""
+# category: case studies
+import altair as alt
+from vega_datasets import data
+
+source = data.weather()
+
+base = alt.Chart(source).encode(
+    x=alt.X('id:O',
+            axis=alt.Axis(
+                domain=False,
+                ticks=False,
+                labels=False,
+                title=None,
+                titlePadding=25,
+                orient='top'
+            )
+            ),
+)
+
+chart = base.mark_bar(
+    style='box'
+).encode(
+    y=alt.Y('record.low:Q',
+            scale=alt.Scale(domain=[10, 70]),
+            axis=alt.Axis(title='Temperature (F)')
+            ),
+    y2='record.high:Q',
+    size=alt.value(20),
+    color=alt.value('#ccc')
+)
+
+chart += base.mark_bar(
+    style='box'
+).encode(
+    y='normal.low:Q',
+    y2='normal.high:Q',
+    size=alt.value(20),
+    color=alt.value('#999')
+)
+
+chart += base.mark_bar(
+    style='box'
+).encode(
+    y='actual.low:Q',
+    y2='actual.high:Q',
+    size=alt.value(12),
+    color=alt.value('#000')
+)
+
+chart += base.mark_bar(
+    style='box'
+).encode(
+    y='forecast.low.low:Q',
+    y2='forecast.low.high:Q',
+    size=alt.value(12),
+    color=alt.value('#000')
+)
+
+chart += base.mark_bar(
+    style='box'
+).encode(
+    y='forecast.low.high:Q',
+    y2='forecast.high.high:Q',
+    size=alt.value(3),
+    color=alt.value('#000')
+)
+
+chart += base.mark_bar(
+    style='box'
+).encode(
+    y='forecast.high.low:Q',
+    y2='forecast.high.high:Q',
+    size=alt.value(12),
+    color=alt.value('#000')
+)
+
+chart += base.mark_text(
+    align='center',
+    baseline='bottom',
+).encode(
+    text='day:N',
+    y=alt.value(-5)
+)
+
+chart.properties(
+    title=['Weekly Weather', 'Observations and Predictions'],
+    width=250,
+    height=200
+).configure_title(
+    frame='group'
+)