如何在R中运行循环以找到7范围内的唯一数字组合？

Question

I have a dataset which looks something like this:-

Key Days
A 1
A 2
A 3
A 8
A 9
A 36
A 37
B 14
B 15
B 44
B 45

I would like to split the individual keys based on the days in groups of 7. For eg:-

Key Days
A 1
A 2
A 3

Key Days
A 8
A 9

Key Days
A 36
A 37

Key Days
B 14
B 15

Key Days
B 44
B 45

I could use ifelse and specify buckets of 1-7, 7-14 etc until 63-70 (max possible value of days). However the issue lies with the days column. There are lots of cases wherein there is an overlap in days - Take days 14-15 as an example which would fall into 2 brackets if split using the ifelse logic (7-14 & 15-21). The ideal method of splitting this would be to identify a day and add 7 to it and check how many rows of data are actually falling under that category. I think we need to use loops for this. I could do it in excel but i have 20000 rows of data for 2000 keys hence i'm using R. I would need a loop which checks each key value and for each key it further checks the value of days and buckets them in group of 7 by checking the first day value of each range.

Answer 1

We create a grouping variable by applying %/% on the 'Day' column and then split the dataset into a list based on that 'grp'.

grp <- df$Day %/%7
split(df, factor(grp, levels = unique(grp)))
#$`0`
#  Key Days
#1   A    1
#2   A    2
#3   A    3

#$`1`
#  Key Days
#4   A    8
#5   A    9

#$`5`
#  Key Days
#6   A   36
#7   A   37

#$`2`
#  Key Days
#8   B   14
#9   B   15

#$`6`
#   Key Days
#10   B   44
#11   B   45

Update

If we need to split by 'Key' also

lst <- split(df, list(factor(grp, levels = unique(grp)), df$Key), drop=TRUE)