Python 比较两个不同日期对应的a值的平均值?
我有一张这样的桌子:Python 比较两个不同日期对应的a值的平均值?,python,pandas,date,average,data-science,Python,Pandas,Date,Average,Data Science,我有一张这样的桌子: Date Student Average(for that date) 17 Jan 2020 Alex 40 18 Jan 2020 Alex 50 19 Jan 2020 Alex 80 20 Jan 2020 Alex 70 17 Jan 2020 Jeff 10 18 Jan 2020 Jeff 50 19
Date Student Average(for that date)
17 Jan 2020 Alex 40
18 Jan 2020 Alex 50
19 Jan 2020 Alex 80
20 Jan 2020 Alex 70
17 Jan 2020 Jeff 10
18 Jan 2020 Jeff 50
19 Jan 2020 Jeff 80
20 Jan 2020 Jeff 60
avg(score)(for current date) < ( avg(score)(for previous day) - (90% * avg(score)(for previous day) /100)
我想为“高”和“低”添加一列。该栏的逻辑应该是,只要学生今天的平均分数大于前几天分数的90%,该栏就应该是高的。
就像我的比较看起来像这样:
Date Student Average(for that date)
17 Jan 2020 Alex 40
18 Jan 2020 Alex 50
19 Jan 2020 Alex 80
20 Jan 2020 Alex 70
17 Jan 2020 Jeff 10
18 Jan 2020 Jeff 50
19 Jan 2020 Jeff 80
20 Jan 2020 Jeff 60
avg(score)(for current date) < ( avg(score)(for previous day) - (90% * avg(score)(for previous day) /100)
avg(分数)(当前日期)<(avg(分数)(前一天)-(90%*avg(分数)(前一天)/100)
我想不出如何将日期部分纳入我的公式中。它会将当天的平均值与前一天的平均值进行比较
我正在与熊猫合作,所以我想知道是否有一种方法可以将其融入其中。IIUC
df['Previous Day'] = df.sort_values('Date').groupby('Student')['Average'].shift()*.90
df['Indicator'] = np.where(df['Average']>df['Previous Day'],'High','Low')
df
输出:
Date Student Average Previous Day Indicator
0 2020-01-17 Alex 40 NaN Low
1 2020-01-18 Alex 50 36.0 High
2 2020-01-19 Alex 80 45.0 High
3 2020-01-20 Alex 70 72.0 Low
4 2020-01-17 Jeff 10 NaN Low
5 2020-01-18 Jeff 50 9.0 High
6 2020-01-19 Jeff 80 45.0 High
7 2020-01-20 Jeff 60 72.0 Low
谢谢:)这对我要找的东西起了作用,但有一点变化。