Python 更改 matplotlib 中日期时间轴的格式
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Changing the formatting of a datetime axis in matplotlib
提问by Sheryl
I have a series whose index is datetimethat I wish to plot. I want to plot the values of the series on the y axis and the index of the series on the x axis. The Serieslooks as follows:
我有一个系列，其索引是datetime我希望绘制的。我想在 y 轴上绘制系列的值，在 x 轴上绘制系列的索引。该Series如下外观：
2014-01-01 7
2014-02-01 8
2014-03-01 9
2014-04-01 8
...
I generate a graph using plt.plot(series.index, series.values). But the graph looks like:
我使用plt.plot(series.index, series.values). 但图形看起来像：
The problem is that I would like to have only year and month. However, the graph contains hours, minutes and seconds. How can I remove them so that I get my desired formatting?
问题是我只想有年和月。但是，图表包含小时、分钟和秒。如何删除它们以便获得所需的格式？
回答by andrew_reece
# sample data
import numpy as np
import pandas as pd
N = 30
drange = pd.date_range("2014-01", periods=N, freq="MS")
values = {'values':np.random.randint(1,20,size=N)}
df = pd.DataFrame(values, index=drange)
# use formatters to specify major and minor ticks
import matplotlib.pyplot as plt
import matplotlib.dates as mdates
fig, ax = plt.subplots()
ax.plot(df.index, df.values)
ax.set_xticks(df.index)
ax.xaxis.set_major_formatter(mdates.DateFormatter("%Y-%m"))
ax.xaxis.set_minor_formatter(mdates.DateFormatter("%Y-%m"))
_=plt.xticks(rotation=90)
回答by Scott Boston
You can try something like this:
你可以尝试这样的事情：
import matplotlib.dates as mdates
import matplotlib.pyplot as plt
df = pd.DataFrame({'values':np.random.randint(0,1000,36)},index=pd.date_range(start='2014-01-01',end='2016-12-31',freq='M'))
fig,ax1 = plt.subplots()
plt.plot(df.index,df.values)
monthyearFmt = mdates.DateFormatter('%Y %B')
ax1.xaxis.set_major_formatter(monthyearFmt)
_ = plt.xticks(rotation=90)
