Question

请参见下面的示例。我想发生的是，条形图（右）始终显示所有xlabel（从A到Z），无论它们是否存在于选择中（在左图中）。我在网上找到了很多有关格式化标签的信息，但没有有关设置标签的信息。我可以以某种方式手动设置xlabel，还是将未经过滤的数据用作xlabel的基础？

import altair as alt
import pandas as pd
import random
import string

random.seed(42)

consultation_dates = pd.date_range(start='1/1/2018', end='1/08/2020')
disease_codes = random.choices(string.ascii_uppercase, k=len(consultation_dates))
consultation_weights = [random.randint(1, 4) for i in range(len(consultation_dates))]

df = pd.DataFrame({'date': consultation_dates,
                  'disease_code': disease_codes,
                  'consultation_weight': consultation_weights})

selected_range = alt.selection_interval(encodings=['x'])

use_over_time = alt.Chart(df).mark_area().encode(
    x='yearquarter(date):Q',
    y='sum(consultation_weight):Q'
).add_selection(
    selected_range
)

use_by_disease = alt.Chart(df).mark_bar().encode(
    x='disease_code:N',
    y='sum(consultation_weight):Q'
).transform_filter(
    selected_range
)

use_over_time | use_by_disease

Answer 1

找到了我自己的答案。可以通过分层来完成！

import altair as alt
import pandas as pd
import random
import string

random.seed(42)

consultation_dates = pd.date_range(start='1/1/2018', end='1/08/2020')
disease_codes = random.choices(string.ascii_uppercase, k=len(consultation_dates))
consultation_weights = [random.randint(1, 4) for i in range(len(consultation_dates))]

df = pd.DataFrame({'date': consultation_dates,
                  'disease_code': disease_codes,
                  'consultation_weight': consultation_weights})

selected_range = alt.selection_interval(encodings=['x'])

use_over_time = alt.Chart(df).mark_area().encode(
    x='yearquarter(date):Q',
    y='sum(consultation_weight):Q'
).add_selection(
    selected_range
)


use_by_disease_base = alt.Chart(df).mark_bar(opacity=0.3).encode(
    x='disease_code:N',
    y='sum(consultation_weight):Q',
    color=alt.value('lightgray')
)
use_by_disease = alt.Chart(df).mark_bar(opacity=0.3).encode(
    x='disease_code:N',
    y='sum(consultation_weight):Q'
).transform_filter(
    selected_range
)

use_over_time | (use_by_disease_base + use_by_disease)

Altair交互式图表：显示所有轴标签，而transform_filter仅获取部分数据

1 个答案: