有没有办法在 Altair 图表中隐藏空值？

Question

我不想在我的 Altair 图表上显示空值。有什么方法可以做到这一点，而无需在绘制图表之前将它们从我的数据中删除？

我有一个数据框：

           d7_rent_own d8a_moving
0              Rent        NaN
1               Own         No
2               Own         No
3              Rent         No
4               Own         No
5              Rent         No
6              Rent        Yes
7               Own         No
8               Own         No
9               Own         No
10              Own         No
11              Own        Yes
12              Own         No
13             Rent        Yes
14             Rent         No
15              Own         No
16              Own         No
17              Own         No
18              Own         No
19              Own         No
20              Own         No
21             Rent        Yes
22              Own         No
23              Own         No
24              Own         No
25  No Answer Given        NaN
26             Rent        NaN
27             Rent         No
28              Own         No
29  No Answer Given        NaN
30              Own        NaN
31             Rent        Yes
32  No Answer Given         No
33             Rent        Yes
34              Own         No
35              Own        Yes
36             Rent         No
37             Rent         No
38              Own        NaN
39              Own         No
40             Rent        NaN
41             Rent        Yes
42             Rent        Yes
43             Rent         No
44              Own         No
45              Own         No
46             Rent         No
47             Rent        Yes
48             Rent         No
49             Rent         No

我正在制作条形图：

alt.Chart(df_ex).mark_bar().encode(
  alt.X('d7_rent_own:N', title = 'Housing Status'),
  alt.Y('count():Q', title = 'Number of Responses'),
  color = alt.Color('d8a_moving:N', legend=alt.Legend(title='Do you plan to move away?')))

但它是这样显示的，带有空值：

Answer 1

您可以在将数据传递给 Altair 时使用 pandas dropna 将其删除。这将避免将它们从存储在变量 df_ex.

中的数据框中删除

alt.Chart(df_ex.dropna()).mark_bar().encode(
  alt.X('d7_rent_own:N', title = 'Housing Status'),
  alt.Y('count():Q', title = 'Number of Responses'),
  color = alt.Color('d8a_moving:N', legend=alt.Legend(title='Do you plan to move away?')))

您也可以在 Altair 中使用转换过滤器来获得相同的结果：

alt.Chart(df_ex).mark_bar().encode(
  alt.X('d7_rent_own:N', title = 'Housing Status'),
  alt.Y('count():Q', title = 'Number of Responses'),
  color = alt.Color('d8a_moving:N', legend=alt.Legend(title='Do you plan to move away?'))
).transform_filter(
    'isValid(datum.d8a_moving)'
)

有没有办法在 Altair 图表中隐藏空值？

Is there a way to hide nulls in an Altair chart?

null

charts

altair