Python 如何使用 matplotlib 中的日期时间更改 x 轴的范围？
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How do I change the range of the x-axis with datetimes in matplotlib?
提问by aled1027
I'm trying to plot a graph of dates on the x-axis and values on the y-axis. It works fine, except that I can't get the range of the x-axis to be appropriate. The x-axis range is always Jan 2012 to Jan 2016, despite my dates being from today. I am even specifying that xlim should be the first and last date.
我试图在 x 轴上绘制日期图，在 y 轴上绘制值。它工作正常，除了我无法获得合适的 x 轴范围。尽管我的日期是从今天开始，但 x 轴范围始终是 2012 年 1 月到 2016 年 1 月。我什至指定 xlim 应该是第一个和最后一个日期。
I'm writing this for python-django, if that's relevant.
如果相关，我正在为 python-django 写这个。
import datetime
import matplotlib.pyplot as plt
x = [datetime.date(2014, 1, 29), datetime.date(2014, 1, 29), datetime.date(2014, 1, 29)]
y = [2, 4, 1]
fig, ax = plt.subplots()
ax.plot_date(x, y)
ax.set_xlim([x[0], x[-1]])
canvas = FigureCanvas(plt.figure(1))
response = HttpResponse(content_type='image/png')
canvas.print_png(response)
return response
And here is the output:
这是输出：
采纳答案by Paul H
Edit:
编辑：
Having seen actual data from the OP, all of the values are at the same date/time. So matplotlib is automatically zooming the x-axis out. You can still manually set the x-axis limits with datetimeobjects
从 OP 看到实际数据后，所有值都在同一日期/时间。所以 matplotlib 会自动缩小 x 轴。您仍然可以手动设置datetime对象的 x 轴限制
If I do something like this on matplotlib v1.3.1:
如果我在 matplotlib v1.3.1 上做这样的事情：
import datetime
import matplotlib.pyplot as plt
x = [datetime.date(2014, 1, 29)] * 3
y = [2, 4, 1]
fig, ax = plt.subplots()
ax.plot_date(x, y, markerfacecolor='CornflowerBlue', markeredgecolor='white')
fig.autofmt_xdate()
ax.set_xlim([datetime.date(2014, 1, 26), datetime.date(2014, 2, 1)])
ax.set_ylim([0, 5])
I get:
我得到：
And the axes limits match the dates that I specified.
轴限制与我指定的日期相匹配。
