How to match two vectors with missing values?

Question

I have two vectors of the same length and I am trying to combine them so that they fill in the missing values. For example:

a=c("",1,2,"")
b=c(5,"","",6)

I am looking for this output:

5 1 2 6

Thank you so much

+3

r

Mohammad June 17. At 1:41

5 answers

and

as.numeric(paste(a,b))
[1] 5 1 2 6

+5

Pierre lafortune June 17. At 4:44 am

Or:

a[a==""] <- b[b!=""]
as.numeric(a)
# [1] 5 1 2 6

+4

Carlos cinelli June 17. 15 at 2:04

a[a == ""] <- 0
b[b == ""] <- 0

a <- as.numeric(a)
b <- as.numeric(b)

output <- a + b

+3

Alex June 17. '15 at 1:44

as.numeric(ifelse(a != "", a, b))

+3

jenesaisquoi June 17. At 1:49 am

thelatemail · Accepted Answer · 2015-06-17T02:03:20+0000

In this case, normal numeric comparison via pmax

also works:

as.numeric(pmax(a,b))
#[1] 5 1 2 6

This is because R resorts to alphanumeric sorting when max

/ min

etc. apply to character data:

max(c("b","a"))
#[1] "b"