问题
How do I merge (add) contingency tables:
> (t1 <- table(c("a","b","b","c")))
a b c
1 2 1
> (t2 <- table(c("c","d","d","a")))
a c d
1 1 2
I want this:
a b c d
2 2 2 2
回答1:
You can do it using split
and sapply
> T <- c(t1, t2)
> sapply(split(T, names(T)), sum)
a b c d
2 2 2 2
Or directly using tapply
as pointed out by @Arun
> tapply(T, names(T), sum)
a b c d
2 2 2 2
回答2:
Here is what I was able to come up with:
> (t1 <- table(c("a","b","b","c")))
a b c
1 2 1
> (t2 <- table(c("c","d","d","a")))
a c d
1 1 2
> (n <- sort(union(names(t1),names(t2))))
[1] "a" "b" "c" "d"
> (t1 <- t1[n])
a b c <NA>
1 2 1 NA
> names(t1) <- n
> t1
a b c d
1 2 1 NA
> t1[is.na(t1)] <- 0
> t1
a b c d
1 2 1 0
> t2 <- t2[n]
> names(t2) <- n
> t2
a b c d
1 NA 1 2
> t2[is.na(t2)] <- 0
> t2
a b c d
1 0 1 2
> t1+t2
a b c d
2 2 2 2
I think there must be a better way...
回答3:
This works:
library(plyr)
colSums(rbind.fill(data.frame(t(unclass(t1))), data.frame(t(unclass(t2)))),
na.rm = T)
来源:https://stackoverflow.com/questions/17030647/how-to-sum-counts-across-tables-that-may-contain-partially-different-categories