matplotlib 中以日期为 x 轴的最简单直方图

Question

我一直在尝试正确显示一个简单的直方图，其中日期为 x 轴，整数为 y 轴。下面的示例恰好是一个子图（2 个 y 轴，1 个共享 x 轴），但问题不存在，而是 hist 本身。

import datetime
import matplotlib
matplotlib.use('agg')   # server no need to display graphics
import matplotlib.pyplot as plt

# x-axis is 3 consecutive dates (days)
now = datetime.datetime.now().date()
x = [now, now + datetime.timedelta(days=1), now + datetime.timedelta(days=2)]

# y1-axis is 3 numbers
y1 = [10, 0, 3]
y2 = [8, 0, 3]

fig, axarr = plt.subplots(2, sharex=True)
bins = range(1, len(x) + 1)
axarr[1].hist(y1, bins=len(x), edgecolor="k")
axarr[1].set_xticks(bins)
axarr[1].set_xticklabels(x)
axarr[1].set_yticks(range(0, max(y1) + 1))

# axarr[0] ommitted for simplicity

plt.savefig('a.png', bbox_inches='tight')

但是我得到的图像是......

Answer 1

您可能需要bar 图表。

import datetime
import matplotlib
matplotlib.use('agg')   # server no need to display graphics
import matplotlib.pyplot as plt

# x-axis is 3 consecutive dates (days)
now = datetime.datetime.now().date()
x = [now, now + datetime.timedelta(days=1), now + datetime.timedelta(days=2)]

# y1-axis is 3 numbers
y1 = [10, 0, 3]
y2 = [8, 0, 3]

fig, axarr = plt.subplots(2, sharex=True)
bins = range(1, len(x) + 1)
axarr[1].bar(x, y1, edgecolor="k")
axarr[1].set_xticks(x)
axarr[1].set_xticklabels(x)

plt.savefig('a.png', bbox_inches='tight')

Answer 2

如果您希望在直方图的 x 轴上显示日期，则需要将日期作为 hist 的参数。

now = datetime.datetime.now().date()
x = [now, now + datetime.timedelta(days=1), now + datetime.timedelta(days=2)]

axarr[1].hist(x, edgecolor="k")