Please forgive me if I missed an answer to such a simple question.
I want to use cbind()
to bind two columns. One of them is a single entry shorter in length.
Can I have R supply an NA
for the missing value?
The documentation discusses a deparse.level
argument but this doesn't seem to be my solution.
Further, if I may be so bold, would there also be a quick way to prepend the shorter column with NA
's?
Try this:
x <- c(1:5)
y <- c(4:1)
length(y) = length(x)
cbind(x,y)
x y
[1,] 1 4
[2,] 2 3
[3,] 3 2
[4,] 4 1
[5,] 5 NA
or this:
x <- c(4:1)
y <- c(1:5)
length(x) = length(y)
cbind(x,y)
x y
[1,] 4 1
[2,] 3 2
[3,] 2 3
[4,] 1 4
[5,] NA 5
I think this will do something similar to what DWin suggested and work regardless of which vector is shorter:
x <- c(4:1)
y <- c(1:5)
lengths <- max(c(length(x), length(y)))
length(x) <- lengths
length(y) <- lengths
cbind(x,y)
The code above can also be condensed to:
x <- c(4:1)
y <- c(1:5)
length(x) <- length(y) <- max(c(length(x), length(y)))
cbind(x,y)
EDIT
Here is what I came up with to address the question:
"Further, if I may be so bold, would there also be a quick way to prepend the shorter column with NA's?"
inserted into the original post by Matt O'Brien.
x <- c(4:1)
y <- c(1:5)
first <- 1 # 1 means add NA to top of shorter vector
# 0 means add NA to bottom of shorter vector
if(length(x)<length(y)) {
if(first==1) x = c(rep(NA, length(y)-length(x)),x);y=y
if(first==0) x = c(x,rep(NA, length(y)-length(x)));y=y
}
if(length(y)<length(x)) {
if(first==1) y = c(rep(NA, length(x)-length(y)),y);x=x
if(first==0) y = c(y,rep(NA, length(x)-length(y)));x=x
}
cbind(x,y)
# x y
# [1,] NA 1
# [2,] 4 2
# [3,] 3 3
# [4,] 2 4
# [5,] 1 5
Here is a function:
x <- c(4:1)
y <- c(1:5)
first <- 1 # 1 means add NA to top of shorter vector
# 0 means add NA to bottom of shorter vector
my.cbind <- function(x,y,first) {
if(length(x)<length(y)) {
if(first==1) x = c(rep(NA, length(y)-length(x)),x);y=y
if(first==0) x = c(x,rep(NA, length(y)-length(x)));y=y
}
if(length(y)<length(x)) {
if(first==1) y = c(rep(NA, length(x)-length(y)),y);x=x
if(first==0) y = c(y,rep(NA, length(x)-length(y)));x=x
}
return(cbind(x,y))
}
my.cbind(x,y,first)
my.cbind(c(1:5),c(4:1),1)
my.cbind(c(1:5),c(4:1),0)
my.cbind(c(1:4),c(5:1),1)
my.cbind(c(1:4),c(5:1),0)
my.cbind(c(1:5),c(5:1),1)
my.cbind(c(1:5),c(5:1),0)
This version allows you to cbind two vectors of different mode:
x <- c(4:1)
y <- letters[1:5]
first <- 1 # 1 means add NA to top of shorter vector
# 0 means add NA to bottom of shorter vector
my.cbind <- function(x,y,first) {
if(length(x)<length(y)) {
if(first==1) x = c(rep(NA, length(y)-length(x)),x);y=y
if(first==0) x = c(x,rep(NA, length(y)-length(x)));y=y
}
if(length(y)<length(x)) {
if(first==1) y = c(rep(NA, length(x)-length(y)),y);x=x
if(first==0) y = c(y,rep(NA, length(x)-length(y)));x=x
}
x <- as.data.frame(x)
y <- as.data.frame(y)
return(data.frame(x,y))
}
my.cbind(x,y,first)
# x y
# 1 NA a
# 2 4 b
# 3 3 c
# 4 2 d
# 5 1 e
my.cbind(c(1:5),letters[1:4],1)
my.cbind(c(1:5),letters[1:4],0)
my.cbind(c(1:4),letters[1:5],1)
my.cbind(c(1:4),letters[1:5],0)
my.cbind(c(1:5),letters[1:5],1)
my.cbind(c(1:5),letters[1:5],0)