居中TickLabels
有时将ticklabels置于中心是件好事。 Matplotlib目前将标签与刻度线关联,标签可以使用水平对齐属性对齐“中心”,“左”或“右”:
ax.xaxis.set_tick_params(horizontalalignment='right')
但这并没有帮助将标签置于刻度之间。一种解决方案是“伪造它”。 使用次要刻度在主要刻度之间放置一个刻度。这是一个标记月份的示例,以ticks为中心。
import numpy as np
import matplotlib.cbook as cbook
import matplotlib.dates as dates
import matplotlib.ticker as ticker
import matplotlib.pyplot as plt
# load some financial data; apple's stock price
with cbook.get_sample_data('aapl.npz') as fh:
r = np.load(fh)['price_data'].view(np.recarray)
r = r[-250:] # get the last 250 days
# Matplotlib works better with datetime.datetime than np.datetime64, but the
# latter is more portable.
date = r.date.astype('O')
fig, ax = plt.subplots()
ax.plot(date, r.adj_close)
ax.xaxis.set_major_locator(dates.MonthLocator())
ax.xaxis.set_minor_locator(dates.MonthLocator(bymonthday=15))
ax.xaxis.set_major_formatter(ticker.NullFormatter())
ax.xaxis.set_minor_formatter(dates.DateFormatter('%b'))
for tick in ax.xaxis.get_minor_ticks():
tick.tick1line.set_markersize(0)
tick.tick2line.set_markersize(0)
tick.label1.set_horizontalalignment('center')
imid = len(r) // 2
ax.set_xlabel(str(date[imid].year))
plt.show()