matplotlib 中的日期刻度和旋转 [英] Date ticks and rotation in matplotlib

问题描述

我在尝试在 matplotlib 中旋转日期刻度时遇到问题.下面是一个小示例程序.如果我尝试在最后旋转刻度线，则刻度线不会旋转.如果我尝试按照注释崩溃"下所示旋转刻度，则 matplot lib 会崩溃.

I am having an issue trying to get my date ticks rotated in matplotlib. A small sample program is below. If I try to rotate the ticks at the end, the ticks do not get rotated. If I try to rotate the ticks as shown under the comment 'crashes', then matplot lib crashes.

仅当 x 值为日期时才会发生这种情况.如果我在调用 avail_plot 时将变量 dates 替换为变量 t，则 xticks(rotation=70) 调用在 avail_plot 中工作得很好.

This only happens if the x-values are dates. If I replaces the variable dates with the variable t in the call to avail_plot, the xticks(rotation=70) call works just fine inside avail_plot.

有什么想法吗?

import numpy as np
import matplotlib.pyplot as plt
import datetime as dt

def avail_plot(ax, x, y, label, lcolor):
    ax.plot(x,y,'b')
    ax.set_ylabel(label, rotation='horizontal', color=lcolor)
    ax.get_yaxis().set_ticks([])

    #crashes
    #plt.xticks(rotation=70)

    ax2 = ax.twinx()
    ax2.plot(x, [1 for a in y], 'b')
    ax2.get_yaxis().set_ticks([])
    ax2.set_ylabel('testing')

f, axs = plt.subplots(2, sharex=True, sharey=True)
t = np.arange(0.01, 5, 1)
s1 = np.exp(t)
start = dt.datetime.now()
dates=[]
for val in t:
    next_val = start + dt.timedelta(0,val)
    dates.append(next_val)
    start = next_val

avail_plot(axs[0], dates, s1, 'testing', 'green')
avail_plot(axs[1], dates, s1, 'testing2', 'red')
plt.subplots_adjust(hspace=0, bottom=0.3)
plt.yticks([0.5,],("",""))
#doesn't crash, but does not rotate the xticks
#plt.xticks(rotation=70)
plt.show()

推荐答案

如果您更喜欢非面向对象的方法，请将 plt.xticks(rotation=70) 移动到右侧 之前 两个 avail_plot 调用，例如

If you prefer a non-object-oriented approach, move plt.xticks(rotation=70) to right before the two avail_plot calls, eg

plt.xticks(rotation=70)
avail_plot(axs[0], dates, s1, 'testing', 'green')
avail_plot(axs[1], dates, s1, 'testing2', 'red')

这会在设置标签之前设置旋转属性.由于这里有两个轴，plt.xticks 在绘制两个图后会感到困惑.当 plt.xticks 不做任何事情时，plt.gca() 不会不给你想要修改的轴，因此作用于当前轴的 plt.xticks 将不起作用.

This sets the rotation property before setting up the labels. Since you have two axes here, plt.xticks gets confused after you've made the two plots. At the point when plt.xticks doesn't do anything, plt.gca() does not give you the axes you want to modify, and so plt.xticks, which acts on the current axes, is not going to work.

对于不使用 plt.xticks 的面向对象方法，您可以使用

For an object-oriented approach not using plt.xticks, you can use

plt.setp( axs[1].xaxis.get_majorticklabels(), rotation=70 )

在两次 avail_plot 调用之后.这会专门设置正确轴上的旋转.

after the two avail_plot calls. This sets the rotation on the correct axes specifically.

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