For example,
dateIntervals <- as.Date(c("2020-08-10", "2020-11-11", "2021-07-05"))
possibleDates <- seq(as.Date("2020-01-02"), dateIntervals[3], by = "day")
genDF<-function() data.frame(Date = sample(possibleDates, 100), Value = runif(100))
listdf <-replicate(2, genDF(), simplify = FALSE)
Yes, listdf has two dataframe elements(each 100 random dates in possibleDates and values) and listdf[[1]] is like this
A data.frame: 100 × 2
Date Value
<date> <dbl>
2020-07-24 0.63482411
2020-02-26 0.25989280
2020-10-26 0.21721077
2020-10-11 0.34774192
2020-08-18 0.67758312
2020-02-03 0.22929624
2020-06-10 0.30279353
2020-05-29 0.95549488
...
lapply(listdf, function(x) split(x, findInterval(x$Date, dateIntervals)))
Made listdf as a 2*3 list, splitted by date.
1.$`0`
A data.frame: 43 × 2
Date Value
<date> <dbl>
1 2020-07-24 0.63482411
2 2020-02-26 0.25989280
6 2020-02-03 0.22929624
7 2020-06-10 0.30279353
...
$`1`
A data.frame: 15 × 2
Date Value
<date> <dbl>
3 2020-10-26 0.21721077
4 2020-10-11 0.34774192
5 2020-08-18 0.67758312
31 2020-11-09 0.59149301
...
$`2`
A data.frame: 42 × 2
Date Value
<date> <dbl>
9 2021-06-28 0.10055644
10 2021-05-17 0.63942936
12 2021-04-22 0.63589801
13 2021-02-01 0.70106156
...
2.$`0`
A data.frame: 43 × 2
Date Value
<date> <dbl>
2 2020-07-16 0.81376364
4 2020-07-03 0.05152627
7 2020-01-21 0.98677433
8 2020-03-23 0.13513921
...
$`1`
A data.frame: 18 × 2
Date Value
<date> <dbl>
5 2020-11-01 0.02740125
12 2020-09-04 0.82042568
15 2020-08-12 0.54190868
16 2020-09-19 0.05933666
18 2020-10-05 0.04983061
...
$`2`
A data.frame: 38 × 2
Date Value
<date> <dbl>
1 2021-04-13 0.46199245
3 2021-06-12 0.71461155
6 2021-01-24 0.56527997
9 2021-04-17 0.72634151
13 2021-04-20 0.55489499
...
I want only first two of the splitted ones.($'0' and $'1' for 1. and 2.)
is there any parameter in the split function which does things like this? (getting only first or last n elements) I want something like this...
lapply(listdf, function(x) split(x, findInterval(x$Date, dateIntervals), some parameter=2))
yes this "2". Getting only the first two ones. is there a function parameter in split which can do this?