def test_chart_infer_types():
data = pd.DataFrame({'x': pd.date_range('2012', periods=10, freq='Y'),
'y': range(10),
'c': list('abcabcabca')})
def _check_encodings(chart):
dct = chart.to_dict()
assert dct['encoding']['x']['type'] == 'temporal'
assert dct['encoding']['x']['field'] == 'x'
assert dct['encoding']['y']['type'] == 'quantitative'
assert dct['encoding']['y']['field'] == 'y'
assert dct['encoding']['color']['type'] == 'nominal'
assert dct['encoding']['color']['field'] == 'c'
# Pass field names by keyword
chart = alt.Chart(data).mark_point().encode(x='x', y='y', color='c')
_check_encodings(chart)
# pass Channel objects by keyword
chart = alt.Chart(data).mark_point().encode(x=alt.X('x'), y=alt.Y('y'),
color=alt.Color('c'))
_check_encodings(chart)
# pass Channel objects by value
chart = alt.Chart(data).mark_point().encode(alt.X('x'), alt.Y('y'),
alt.Color('c'))
_check_encodings(chart)
# override default types
chart = alt.Chart(data).mark_point().encode(alt.X('x', type='nominal'),
alt.Y('y', type='ordinal'))
dct = chart.to_dict()
assert dct['encoding']['x']['type'] == 'nominal'
assert dct['encoding']['y']['type'] == 'ordinal'
def plot_rental_by_time(df, time_unit = "weekday"):
field_dict= {
"weekday": "weekday_num",
"month" : 'mnth'
}
sort_field = field_dict[time_unit]
casual_plt = alt.Chart(df).mark_bar().encode(y=alt.Y(time_unit, sort=alt.EncodingSortField(
field=sort_field, order="ascending", op='sum')), x=alt.X('casual', title="Rental Count")).properties(title="Casual")
registered_plt = alt.Chart(df).mark_bar().encode(y=alt.Y(time_unit, sort=alt.EncodingSortField(
field=sort_field, order="ascending", op='sum')), x=alt.X('registered', title="Rental Count")).properties(title='Registered')
total_plt = alt.Chart(df).mark_bar().encode(y=alt.Y(time_unit, sort=alt.EncodingSortField(
field=sort_field, order="ascending", op='sum')), x=alt.X('cnt', title='Rental Count')).properties(title="Total")
combined_plt = alt.vconcat(
casual_plt, registered_plt, total_plt)
combined_plt = combined_plt.resolve_scale(
x='shared').properties(title="Rental Number by Weekday")
return combined_plt