使用matplotlib和python绘制datetime.timedelta

Question

我正在处理一项任务，我需要计算每天花费的时间，然后使用条形图来表示时间，所以对于这个任务，我使用python并且能够在每天花费时间并将其存储起来在列表＆＃34; time_list＆＃34;中，现在我不了解如何使用matplotlib函数绘制它。 问题是，此列表包含datetime.timedelta类值。 例如：

time_list
[datetime.timedelta(0, 23820), datetime.timedelta(0, 27480), datetime.timedelta(0, 28500), datetime.timedelta(0, 24180), datetime.timedelta(0, 27540), datetime.timedelta(0, 28920), datetime.timedelta(0, 28800), datetime.timedelta(0, 29100), datetime.timedelta(0, 29100), datetime.timedelta(0, 24480), datetime.timedelta(0, 27000)]

这些价​​值意义如下：

Total Time Spent on  2  is  6:37:00
Total Time Spent on  3  is  7:38:00
Total Time Spent on  4  is  7:55:00
Total Time Spent on  5  is  6:43:00
Total Time Spent on  8  is  7:39:00
Total Time Spent on  9  is  8:02:00
Total Time Spent on  10  is  8:00:00
Total Time Spent on  11  is  8:05:00
Total Time Spent on  12  is  8:05:00
Total Time Spent on  15  is  6:48:00
Total Time Spent on  16  is  7:30:00

有人可以帮我策划这个。 提前致谢

Answer 1

我认为你不能在Matplotlib中直接绘制timedelta，但由于你已经有秒数，你可以定义一个自定义刻度格式，将秒转换为小时和分钟。

from matplotlib.ticker import FuncFormatter

def format_func(x, pos):
    hours = int(x//3600)
    minutes = int((x%3600)//60)
    seconds = int(x%60)

    return "{:d}:{:02d}".format(hours, minutes)
    # return "{:d}:{:02d}:{:02d}".format(hours, minutes, seconds)

formatter = FuncFormatter(format_func)

然后，您可以为y轴设置刻度格式化程序。

以下是使用bar的示例。

labels = [2, 3, 4, 5, 8, 9, 10, 11, 12, 15, 16]
seconds = [i.seconds for i in time_list]
f = plt.figure()
ax = f.add_subplot(1,1,1)
ax.bar(labels, seconds)

ax.yaxis.set_major_formatter(formatter)
# this locates y-ticks at the hours
ax.yaxis.set_major_locator(matplotlib.ticker.MultipleLocator(base=3600))
# this ensures each bar has a 'date' label
ax.xaxis.set_major_locator(matplotlib.ticker.MultipleLocator(base=1))

Answer 2

虽然matplotlib原则上可以处理日期时间对象，但条形图无法直接解释它们。因此，可以向timedeltas添加任意日期并使用matplotlib.dates.date2num()转换为数字。然后使用DateFormatter启用不错的刻度标记。

import numpy as np
import datetime
import matplotlib.pyplot as plt
import matplotlib.dates as mdates

days = [2, 3, 4, 5, 8, 9, 10, 11, 12, 15, 16]

time_list = [datetime.timedelta(0, 23820), datetime.timedelta(0, 27480), 
             datetime.timedelta(0, 28500), datetime.timedelta(0, 24180), 
             datetime.timedelta(0, 27540), datetime.timedelta(0, 28920), 
             datetime.timedelta(0, 28800), datetime.timedelta(0, 29100), 
             datetime.timedelta(0, 29100), datetime.timedelta(0, 24480), 
             datetime.timedelta(0, 27000)]

# specify a date to use for the times
zero = datetime.datetime(2018,1,1)
time = [zero + t for t in time_list]
# convert datetimes to numbers
zero = mdates.date2num(zero)
time = [t-zero for t in mdates.date2num(time)]

f = plt.figure()
ax = f.add_subplot(1,1,1)

ax.bar(days, time, bottom=zero)
ax.yaxis_date()
ax.yaxis.set_major_formatter(mdates.DateFormatter("%H:%M"))

# add 10% margin on top (since ax.margins seems to not work here)
ylim = ax.get_ylim()
ax.set_ylim(None, ylim[1]+0.1*np.diff(ylim))

plt.show()

Answer 3

当我想用等于y axis类型的Timedelta64[ns]绘制数据时，我遇到了类似的问题。我从以下博客中找到了解决此问题的最简单解决方案：solution。简而言之，只需将列的dtype更改为.astype('timedelta64[m]')。您只需更改方括号中的值，即可将其更改为小时，分钟或秒。它将y列的dtype更改为float64，然后您可以轻松绘制条形图或以正常单位而不是纳秒的方式绘制