python中x轴上带有日期时间的绘图中的阴影区域(axhspan,matplotlib) [英] Shade area in plot with datetime on xaxis (axhspan, matplotlib) in python
问题描述
我有一个类似的pd df,每列大约有6000个条目:
I have a pd df like that with around 6000 entries per column:
datetime value flag date
0 2015-01-01 07:00:00 0.018013 0.0 2015-01-01
1 2015-01-01 07:06:00 0.101957 1.0 2015-01-01
2 2015-01-01 07:12:00 0.141712 1.0 2015-01-01
3 2015-01-01 07:18:00 0.178875 0.0 2015-01-01
4 2015-01-01 07:24:00 0.237765 0.0 2015-01-01
... ... ... ...
现在,我想在x轴上绘制日期时间,在y轴上绘制值,并在标记= 0时阴影区域.,而不是一条线(使用axvline可以)但整个6分钟,直到下一次测量.而且我想每天创建一个绘图,这就是为什么它以for循环开头的原因.
Now I want to plot the datetime on the x-axis and the value on the y-axis and shade the area when the flag = 0. but not a line (with axvline it works) but the whole 6 minutes until the next measurement. And I want to create one plot per day, that is why it starts with a for loop.
我尝试过这样的事情:
import pandas as pd
import matplotlib.pyplot as plt
for date in df.date.unique():
fig, ax = plt.subplots(nrows=1, ncols=1)
ax.plot('datetime', 'value', data=df[df.date == date])
for flags in df[(df.date == date) & (df.flag == 0.)].datetime:
ax.axhspan(flags, flags+pd.Timedelta(minutes=6), facecolor='0.5', alpha=0.5)
当我尝试这个时,即使 flags
、flags+pd.Timedelta(minutes=6)
和 df 中的条目,我也会收到以下错误.datetime
的类型为:pandas._libs.tslibs.timestamps.Timestamp
When I try this, I get the following error even though the flags
, flags+pd.Timedelta(minutes=6)
and the entries in df.datetime
have the type: pandas._libs.tslibs.timestamps.Timestamp
ValueError: view limit minimum -36835.18135207975 is less than 1 and is an invalid Matplotlib date value. This often happens if you pass a non-datetime value to an axis that has datetime units
有人知道它是如何工作的吗?提前致谢!
Does anyone have any idea how it could work? Thanks in advance!
推荐答案
我是这样想出来的:不幸的是我使用了错误的命令,我必须使用 axvspan 而不是 axhspan.绘图与:
I figured it out this way: Unfortunately I used the wrong command, I have to use axvspan instead of axhspan. The plotting worked with:
ax.axvspan(mdates.date2num(flags), mdates.date2num(flags+pd.Timedelta(minutes=6)), facecolor='0.5', alpha=0.5)
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