如何在matplotlib中以'%H:%M'格式在y轴上绘制时间? [英] how to plot time on y-axis in '%H:%M' format in matplotlib?
问题描述
我想绘制datetime64系列的时间,其中y轴的格式为'%H:%M,仅显示00:00、01:00、02:00等.
i would like to plot the times from a datetime64 series, where the y-axis is formatted as '%H:%M, showing only 00:00, 01:00, 02:00, etc.
这是在不自定义y轴格式的情况下绘制的图.
this is what the plot looks like without customizing the y-axis formatting.
import numpy as np
import pandas as pd
import matplotlib.pyplot as plt
from matplotlib.dates import DateFormatter
from matplotlib.dates import HourLocator
df = pd.DataFrame(data=dict(a=pd.date_range('1/1/2011',periods=1440000,freq='1min')))
df = df.iloc[np.arange(0,1440*100,1440)+np.random.randint(1,300,100)]
plt.plot(df.index,df['a'].dt.time)
plt.show()
阅读有关SO的主题后,我尝试了以下操作,但没有成功.
After reading around on the topic on SO, I attempted the following but without success.
ax = plt.subplot()
ax.yaxis.set_major_locator(HourLocator())
ax.yaxis.set_major_formatter(DateFormatter('%H:%M'))
plt.plot(df.index,df['a'].dt.time)
plt.show()
ValueError: DateFormatter found a value of x=0, which is an illegal date. This usually occurs because you have not informed the axis that it is plotting dates, e.g., with ax.xaxis_date()
有人可以劝我吗?
推荐答案
要实现此目的,您需要传递datetime
对象(我的意思是datetime
,而不是datetime64
).您可以将所有时间戳转换为相同的日期,然后使用.tolist()
获取实际的datetime
对象.
For that to work you need to pass datetime
objects (and I mean datetime
, not datetime64
). You can convert all timestamps to the same date and then use .tolist()
to get the actual datetime
objects.
y = df['a'].apply(lambda x: x.replace(year=1967, month=6, day=25)).tolist()
ax = plt.subplot()
ax.plot(df.index, y)
ax.yaxis.set_major_locator(HourLocator())
ax.yaxis.set_major_formatter(DateFormatter('%H:%M'))
这篇关于如何在matplotlib中以'%H:%M'格式在y轴上绘制时间?的文章就介绍到这了,希望我们推荐的答案对大家有所帮助,也希望大家多多支持IT屋!