从 Pandas 时间序列生成星期几箱线图的最佳方法

2022-01-11 00:00:00 python pandas time-series boxplot dayofweek

问题描述

我正在尝试为时间序列创建一组星期几的箱线图(例如 5 分钟的温度观察).

i am trying to create a set of day-of-week boxplots for a timeseries (e.g. 5-minute temperature observations).

我的代码:

# ts is our timeseries
ts = df.SomeColumn

dow_map = {}
days = ['MON','TUE','WED','THU','FRI','SAT','SUN']
dow_idx = ts.index.dayofweek

i = 0
for d in days:
    dow_map[d] = ts[dow_idx == i]
    i = i + 1

df = pd.DataFrame(dow_map)
df.boxplot()

结果:

---------------------------------------------------------------------------
Exception                                 Traceback (most recent call last)
<ipython-input-898-6070c45e4c4b> in <module>()
     41     i = i + 1
     42 
---> 43 df = pd.DataFrame(dow_map)
     44 df.boxplot()
...
Exception: Reindexing only valid with uniquely valued Index objects

我确实通过为每周的每一天创建 DataFrame，然后将它们连接到最终的 DataFrame 中找到了成功，但这似乎效率低下...

I did find succcess by creating DataFrames for each day-of-week and then concat-ing them into a final DataFrame, but this seems inefficient...

解决方案

1st 创建数据框并使用 weekdays 方法获取星期几:

1st Create data frame and use weekdays method to get days of week:

import pandas as pd
import numpy.random as random
n=1000
df = pd.DataFrame(random.randn(n), pd.date_range('2010-01-01', periods=n), columns=["data"])
df['Dates'] = df.index
df['week_days'] =df.index.weekday
df

现在旋转该表，以便将 week_days 作为列(也可以将 needdays 更改为天的字符串格式，但留给您.

now pivot that table so that the week_days are as columns (could also change the needdays to string formats of days but leaving that for you.

x =df.pivot(index='Dates', columns='week_days', values='data')
x.boxplot()

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