CODEWITHSUNDEEP
rvectormerge
S2her
S2her

Reputation: 61

How to merge two vectors according to the original indices?

I was hoping to get some help over this problem. I have a vector X with 2,000 elements such that:

X<- c("A12","B5","B8","B19","A32","A25","B11","A2","A41","B51"......)

I extracted the IDs from the vector(A IDs and B IDs) separately. Now I have two vectors, A and B. This step is necessary because the process of obtaining A_values and B_values is different, so I needed to separate the two IDs into two vectors:

A<-c("A12","A32","A25","A2","A41".....)
B<-c("B5","B8","B19","B11","B51"....)

After this I obtained the values corresponding to their ids:

A_values <- c(15,21,22,6,2....)
B_values <-c(3,14,16,25,13....)

Now my problem is to merge the A_values and B_values vectors according to the original indices of Ids as they were in the original vector X. The new X_values vector should be:

X_values<-c(15,3,14,16,21,22,25,6,2,25,13.....)

Any help would be truly appreciated.

Upvotes: 1

Views: 227

Answers (2)

akrun
akrun

Reputation: 886948

We can use the matching index concatenated for 'A', 'B'

c(A_values, B_values)[match(X, c(A, B))]
#[1] 15  3 14 16 21 22 25  6  2 13

data

X<- c("A12","B5","B8","B19","A32","A25","B11","A2","A41","B51")
A<-c("A12","A32","A25","A2","A41")
B<-c("B5","B8","B19","B11","B51")
A_values <- c(15,21,22,6,2)
B_values <- c(3,14,16,25,13)

Upvotes: 0

Ronak Shah
Ronak Shah

Reputation: 388817

You can create a named vector and then subset them using X : 

c(setNames(A_values, A), setNames(B_values, B))[X]
#A12  B5  B8 B19 A32 A25 B11  A2 A41 B51 
# 15   3  14  16  21  22  25   6   2  13

Use unname or as.numeric/as.integer to remove the names if not needed.

Upvotes: 1

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