CODEWITHSUNDEEP
r
Duck
Duck

Reputation: 39605

Matching two dataframes considering two variables have the same levels

I dear I have a problem, I have two dataframes like these:

z=data.frame(x1=c(1,2,5,4,9,1,4,2,9,21),x2=c(2,2,2,4,8,9,1,9,1,1),x3=c("a","b","b","a","a","b","b","b","a","a"))
z1=data.frame(y=c("a","b"),x=c("protein","cell"))

I have been trying to match z with z1 considering that levels in y of z1 are the same that levels in x3 of z and I want a new column that shows variable z of z1 in all the data frame z. I would like some like this; I used match but I don't get that result.

    x1 x2 x3   N
1   1  2  a protein
2   2  2  b    cell
3   5  2  b    cell
4   4  4  a protein
5   9  8  a protein
6   1  9  b    cell
7   4  1  b    cell
8   2  9  b    cell
9   9  1  a protein
10 21  1  a protein

Upvotes: 3

Views: 602

Answers (2)

Tyler Rinker
Tyler Rinker

Reputation: 109874

This approach use the package qdap:

library(qdap)
z$N <- z$x3 %l% z1

Yields:

> z
   x1 x2 x3       N
1   1  2  a protein
2   2  2  b    cell
3   5  2  b    cell
4   4  4  a protein
5   9  8  a protein
6   1  9  b    cell
7   4  1  b    cell
8   2  9  b    cell
9   9  1  a protein
10 21  1  a protein

Upvotes: 0

mnel
mnel

Reputation: 115390

You are looking for merge

You can set by.y and by.x appropriately, as they do not have the same name in both columns

merge(z,z1,by.y='y', by.x = 'x3')
   x3 x1 x2       x
1   a  1  2 protein
2   a 21  1 protein
3   a  4  4 protein
4   a  9  8 protein
5   a  9  1 protein
6   b  5  2    cell
7   b  2  2    cell
8   b  4  1    cell
9   b  2  9    cell
10  b  1  9    cell

To use match something like

z$x <- z1[match(z$x3,z1$y),'x']
z
   x1 x2 x3       x
1   1  2  a protein
2   2  2  b    cell
3   5  2  b    cell
4   4  4  a protein
5   9  8  a protein
6   1  9  b    cell
7   4  1  b    cell
8   2  9  b    cell
9   9  1  a protein
10 21  1  a protein

Upvotes: 3

Related Questions