的Python：剧情时间戳数据帧matplotlib

Question

我随时间的曲线值（即每小时） 我有一个数据帧dfout如下

val  x   y      ID        time 
0 6.0 48.730304 11.594837 0efd2316-feb9-461c-b102-045aef8e22fe 2014-03-10 08:02:02 
1 6.5 48.731639 11.602004 0efd2316-feb9-461c-b102-045aef8e22fe 2014-03-10 08:02:26 
2 7.0 48.740104 11.641433 0efd2316-feb9-461c-b102-045aef8e22fe 2014-03-10 08:04:45 
3 6.5 48.744026 11.648048 0efd2316-feb9-461c-b102-045aef8e22fe 2014-03-10 08:05:11 
4 6.0 48.747356 11.654539 0efd2316-feb9-461c-b102-045aef8e22fe 2014-03-10 08:05:32 
5 5.5 48.749050 11.660844 0efd2316-feb9-461c-b102-045aef8e22fe 2014-03-10 08:05:50 
6 5.0 48.749935 11.666812 0efd2316-feb9-461c-b102-045aef8e22fe 2014-03-10 08:06:10 
7 4.5 48.751007 11.677590 0efd2316-feb9-461c-b102-045aef8e22fe 2014-03-10 08:06:54 
8 4.0 48.742317 11.675558 0efd2316-feb9-461c-b102-045aef8e22fe 2014-03-10 08:08:31 
9 4.5 48.736461 11.675782 0efd2316-feb9-461c-b102-045aef8e22fe 2014-03-10 08:08:55 
10 5.0 48.729659 11.675481 0efd2316-feb9-461c-b102-045aef8e22fe 2014-03-10 08:09:20 
11 5.5 48.725871 11.673145 0efd2316-feb9-461c-b102-045aef8e22fe 2014-03-10 08:09:35 

，我想绘制列val如下

import matplotlib.dates as md 
fig=figure(figsize=(20,10)) 
ax=plt.gca() 
xfmt = md.DateFormatter('%H:%M:%S') 
plt.xticks(rotation=25) 
ax.xaxis.set_major_formatter(xfmt) 
plt.title("Temperature") 
plt.ylabel(r'Temperature, $^{o}C$') 
ax.plot(datenumes,dfout.val, marker='.',lw=0) 

但是我想之间08:00:00到的xlabel小时，因此：08:00:00，09:00:00,10:00:00，...，16:00:00。

Answer 1

只需使用ax.set_xticks()选择滴答的位置并为其提供一个为此目的而创建的对象的自定义列表datetime。 问题是这些对象的标签表示是浮动的。您可以通过创建另一个包含时间字符串的列表来解决此问题，因为您希望它们看起来像，我在此解决方案中称为ticklabels。

import matplotlib.dates as md 
import matplotlib.pyplot as plt 
from datetime import * 

val = [6, 6.5, 7, 6.5, 6, 5.5, 5, 4.5, 4, 4.5, 5, 5.5] 
datenumes = [datetime(2014, 3, 10, 8, 2, 2), 
    datetime(2014, 3, 10, 8, 2, 26), 
    datetime(2014, 3, 10, 10, 4, 45), 
    datetime(2014, 3, 10, 10, 5, 11), 
    datetime(2014, 3, 10, 12, 5, 32), 
    datetime(2014, 3, 10, 12, 5, 50), 
    datetime(2014, 3, 10, 15, 6, 10), 
    datetime(2014, 3, 10, 16, 6, 54), 
    datetime(2014, 3, 10, 17, 8, 31), 
    datetime(2014, 3, 10, 18, 8, 55), 
    datetime(2014, 3, 10, 19, 9, 20), 
    datetime(2014, 3, 10, 22, 9, 35)] 

# creates list of datetimes where ticks should be set 
ticks = [datetime(2014, 3, 10, 8, 0, 0), 
     datetime(2014, 3, 10, 10, 0, 0), 
     datetime(2014, 3, 10, 12, 0, 0), 
     datetime(2014, 3, 10, 14, 0, 0), 
     datetime(2014, 3, 10, 16, 0, 0), 
     datetime(2014, 3, 10, 18, 0, 0), 
     datetime(2014, 3, 10, 20, 0, 0), 
     datetime(2014, 3, 10, 22, 0, 0) ] 

# generate labels for the datetimes used as ticks 
ticklabels = [str(tick)[11:] for tick in ticks] 

# PLOT 
fig=plt.figure(figsize=(20,10)) 
ax=plt.gca() 
plt.xticks(rotation=25) 

# set the ticks according to the list tick 
ax.set_xticks(ticks) 
## set labels to human readable format 
ax.set_xticklabels(ticklabels) 

plt.title("Temperature") 
plt.ylabel(r'Temperature, $^{o}C$') 
ax.plot(datenumes, val, marker='.', lw=0) 
plt.show()