I'm trying to tabulate/map the counts of 2 factor-class vectors (b1 & b2) into a bigger dataframe. Summary of the vectors are as below:
> summary(b1)
(4,6] (6,8] NA's
16 3 1
> summary(b2)
(4,6] (6,8] NA's
9 0 11
I would like to map the above counts into a bigger dataframe:
Intervals b1 b2
1 (-Inf,0] NA NA
2 (0,2] NA NA
3 (2,4] NA NA
4 (4,6] NA NA
5 (6,8] NA NA
6 (8,10] NA NA
7 (10,12] NA NA
8 (12, Inf] NA NA
My question: is there a vectorized or more direct way to do the above without resorting to a 'for' loop + if-else condition checking? It seems like something easily done, but I'm have been having this mental block and I haven't been successful in finding relevant help online. Any help/hint is appreciated. Thanks in advance!
My sample code is attached:
NoOfElement <- 20
MyBreaks <- c(seq(4, 8, by=2))
MyBigBreaks <- c(-Inf, seq(0,12, by=2), Inf)
set.seed(1)
a1 <- rnorm(NoOfElement, 5); a2 <- rnorm(NoOfElement, 4)
b1 <- cut(a1, MyBreaks); b2 <- cut(a2, MyBreaks)
c <- seq(-10, 10)
d <- cut(c, MyBigBreaks)
e <- data.frame( Intervals=levels(d), b1=NA, b2=NA )
The table function does the tabulation that you need. It returns a named vector, and you can compare the names against the column e$Intervals to assign the correct values.
This relies on the fact that the order of the factor levels is the same in e$Intervals and b1 and b2. This is so because these all come from cut.
e$b1[e$Intervals %in% names(table(b1))] <- table(b1)
e$b2[e$Intervals %in% names(table(b2))] <- table(b2)
e
## Intervals b1 b2
## 1 (-Inf,0] NA NA
## 2 (0,2] NA NA
## 3 (2,4] NA NA
## 4 (4,6] 16 9
## 5 (6,8] 3 0
## 6 (8,10] NA NA
## 7 (10,12] NA NA
## 8 (12, Inf] NA NA