python - matplotlib 时间序列图表上的颜色填充

Question

考虑以下 Pandas 数据框:

time                val server   state
2015-01-01 00:00:00 10   server01 normal
2015-01-01 00:02:00 18  server01 high
2015-01-01 00:03:00 41  server01 high
2015-01-01 00:04:00 22  server01 high
2015-01-01 01:05:00 32  server01 normal
2015-01-01 01:06:00 10  server01 high   
2015-01-01 01:07:00 42  server01 normal
2015-01-01 01:08:00 24  server01 normal
...........

在时间序列图表上绘制时，如何绘制 state = high 的区域？

像这样:

Answer 1

由于您想要绘制只有一个 'high' 状态的时间跨度，您需要建立一个人工缓冲区以分别设置高于和低于每个组的最大值和最小值。

p = pd.Timedelta(30, unit='s')

df.val.plot()
for (state, _), g in df.groupby(['state', df.state.ne('high').cumsum()]):
    if  state == 'high':
        start = g.index.min() - p
        end = g.index.max() + p
        plt.axvspan(start, end, color='r', alpha=0.2)