0

I have a named vector (say n) with names as consecutive integers from 1 to 25000, and values associated with it, and another smaller vector (say m), similar to "n", with 21399 elements, with the names starting at 1 and ending at 25000.

I want to add named elements to the vector "m" for the missing names and assign a value of 0 to them.

I did that by creating two data frames with names and values as two columns for both and then doing a left join, but are there any better ways of doing it?

A much smaller example:

> n=c("1"=3,"2"=5,"3"=2,"4"=9,"5"=8)
> n
1 2 3 4 5 
3 5 2 9 8 
> m=c("1"=9,"2"=7,"5"=2)
> m
1 2 5 
9 7 2

I want my final "m" to be:

> m
1 2 3 4 5 
9 7 0 0 2

What I did was: 

> x=data.frame("p"=names(n),n)
> y=data.frame("p"=names(m),m)
> join(x,y,by="p")
  p n m
1 1 3 9
2 2 5 7
3 3 2 0
4 4 9 0
5 5 8 2
Tapajit Dey
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2 Answers2

2

A couple of attempts:

m[setdiff(names(n), names(m))] <- 0
m[order(as.numeric(names(m)))]
#1 2 3 4 5 
#9 7 0 0 2 

m <- c(m,replace(n,,0))
tapply(m, names(m), sum)
#1 2 3 4 5 
#9 7 0 0 2

replace(replace(n,,0), match(names(m),names(n)), m)
#1 2 3 4 5 
#9 7 0 0 2

With NAs instead of 0's:

setNames( m[match(names(n),names(m))], names(n) )
# 1  2  3  4  5 
# 9  7 NA NA  2
thelatemail
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0

We can use this 

x=data.frame("p"=names(n),n)
y=data.frame("p"=names(m),m)


merged = merge (x , y, by ="p", all.x = TRUE)

and to replace "NA" with zero, we have 

merged[is.na(merged)] <- 0

output 

    p n m
  1 1 3 9
  2 2 5 7
  3 3 2 0
  4 4 9 0
  5 5 8 2
MFR
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