i'm trying to create columns to represent min/max after every row within a group.
original df
╔═══════╦═══════╦════════╗ ║ color ║ panel ║ result ║ ╠═══════╬═══════╬════════╣ ║ blue ║ b ║ 4 ║ ║ blue ║ b ║ 3 ║ ║ blue ║ b ║ 3 ║ ║ blue ║ b ║ 5 ║ ║ blue ║ b ║ 4 ║ ║ blue ║ b ║ 7 ║ ║ blue ║ b ║ 1 ║ ║ blue ║ b ║ 5 ║ ║ blue ║ b ║ 3 ║ ║ blue ║ b ║ 2 ║ ╚═══════╩═══════╩════════╝
result trying to get
╔═══════╦═══════╦════════╦═════╦═════╗ ║ color ║ panel ║ result ║ min ║ max ║ ╠═══════╬═══════╬════════╬═════╬═════╣ ║ blue ║ b ║ 4 ║ 4 ║ 4 ║ ║ blue ║ b ║ 3 ║ 3 ║ 4 ║ ║ blue ║ b ║ 3 ║ 3 ║ 4 ║ ║ blue ║ b ║ 5 ║ 3 ║ 5 ║ ║ blue ║ b ║ 4 ║ 3 ║ 5 ║ ║ blue ║ b ║ 7 ║ 3 ║ 7 ║ ║ blue ║ b ║ 1 ║ 1 ║ 7 ║ ║ blue ║ b ║ 5 ║ 1 ║ 7 ║ ║ blue ║ b ║ 3 ║ 1 ║ 7 ║ ║ blue ║ b ║ 2 ║ 1 ║ 7 ║ ╚═══════╩═══════╩════════╩═════╩═════╝
data = {'color':['blue','blue','blue','blue','blue','blue','blue','blue','blue','blue'],
'panel':['b','b','b','b','b','b','b','b','b','b'],
'result':[4,3,3,5,4,7,1,5,3,2]}
kindly advise. thank you
CodePudding user response：
You want cummin and cummax
data.result.cummin()
data.result.cummax()
CodePudding user response：
Use GroupBy.agg with GroupBy.cummax and
GroupBy.cummin and assign to new columns (it is possible, because output is DataFrame with same size like original):
df[['min','max']] = df.groupby(['color','panel'])['result'].agg(['cummin','cummax'])
print (df)
color panel result min max
0 blue b 4 4 4
1 blue b 3 3 4
2 blue b 3 3 4
3 blue b 5 3 5
4 blue b 4 3 5
5 blue b 7 3 7
6 blue b 1 1 7
7 blue b 5 1 7
8 blue b 3 1 7
9 blue b 2 1 7