我在使用 x 轴上带有日期的多个子图时遇到问题。

我正在使用 here 中的 matplotlib 示例.我修改了它以包含另一个子图(绘制的数据是相同的)。这就是我得到的输出:

刻度只出现在第二个子图中。为什么？我怎样才能让它们出现在两个子图中？

这是我修改后的源代码。我添加了代码以在源代码中途的 if block 中包含一个新的子图。

#!/usr/bin/env python
"""
Show how to make date plots in matplotlib using date tick locators and
formatters.  See major_minor_demo1.py for more information on
controlling major and minor ticks

All matplotlib date plotting is done by converting date instances into
days since the 0001-01-01 UTC.  The conversion, tick locating and
formatting is done behind the scenes so this is most transparent to
you.  The dates module provides several converter functions date2num
and num2date

"""
import datetime
import numpy as np
import matplotlib
import matplotlib.pyplot as plt
import matplotlib.dates as mdates
import matplotlib.mlab as mlab
import matplotlib.cbook as cbook

years    = mdates.YearLocator()   # every year
months   = mdates.MonthLocator()  # every month
yearsFmt = mdates.DateFormatter('%Y')

# load a numpy record array from yahoo csv data with fields date,
# open, close, volume, adj_close from the mpl-data/example directory.
# The record array stores python datetime.date as an object array in
# the date column
#datafile = cbook.get_sample_data('goog.npy')
datafile = 'goog.npy'
r = np.load(datafile).view(np.recarray)

fig = plt.figure()
ax = fig.add_subplot(211)
ax.plot(r.date, r.adj_close)


# format the ticks
ax.xaxis.set_major_locator(years)
ax.xaxis.set_major_formatter(yearsFmt)
ax.xaxis.set_minor_locator(months)

datemin = datetime.date(r.date.min().year, 1, 1)
datemax = datetime.date(r.date.max().year+1, 1, 1)
ax.set_xlim(datemin, datemax)

# format the coords message box
def price(x): return '$%1.2f'%x
ax.format_xdata = mdates.DateFormatter('%Y-%m-%d')
ax.format_ydata = price
ax.grid(True)

second = True
if second:
    years    = mdates.YearLocator()   # every year
    months   = mdates.MonthLocator()  # every month
    yearsFmt = mdates.DateFormatter('%Y')

    ax = fig.add_subplot(212)
    ax.plot(r.date, r.adj_close)

    # format the ticks
    ax.xaxis.set_major_locator(years)
    ax.xaxis.set_major_formatter(yearsFmt)
    ax.xaxis.set_minor_locator(months)

    datemin = datetime.date(r.date.min().year, 1, 1)
    datemax = datetime.date(r.date.max().year+1, 1, 1)
    ax.set_xlim(datemin, datemax)

    # format the coords message box
    ax.format_xdata = mdates.DateFormatter('%Y-%m-%d')
    ax.format_ydata = price
    ax.grid(True)

# rotates and right aligns the x labels, and moves the bottom of the
# axes up to make room for them
fig.autofmt_xdate()

plt.show()

最佳答案

我找到了罪魁祸首。这是 autofmt_xdate功能:

Date ticklabels often overlap, so it is useful to rotate them and right align them. Also, a common use case is a number of subplots with shared xaxes where the x-axis is date data. The ticklabels are often long, and it helps to rotate them on the bottom subplot and turn them off on other subplots, as well as turn off xlabels.

这是一个“功能”。您可以通过在每个子图之后插入此代码来实现相同的效果:

plt.xticks(rotation=30)

关于python - x 轴上带有日期的子图，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/8010549/