CODEWITHSUNDEEP
r
moth
moth

Reputation: 2409

indexing one dataframe with another

I have the following subset of two long data.frame:

df1 <- data.frame("trial" = c('SA1','SA2','ES1','SA3','SA4','ES5'), "Genotype" = c('GID1','GID1','GID1','GID2','GID2','GID2'))
df2 <- data.frame('GID1'= c('0','1'),'GID2'=c('1','0'))

What I would like to do is, I want to index df1$Genotype column by df2 colnames and expand df2 columns by substituting the values of df1$trial as new columns in df2.

So as a result I would have df3 as an expansion of df2 as follows :

df3 <- data.frame('SA1'=c(0,1), 'SA2'=c(0,1), 'ES1'=c(0,1), 'SA3'= c(1,0),'SA4'=c(1,0),'ES5'=c(1,0))

Please note the data.frame is huge and I've tried functions like match and %in% without success.

Thanks in advance.

Upvotes: 1

Views: 47

Answers (1)

Julius Vainora
Julius Vainora

Reputation: 48251

It's easier than it seems:

df3 <- df2[df1$Genotype]
colnames(df3) <- df1$trial
df3
#   SA1 SA2 ES1 SA3 SA4 ES5
# 1   0   0   0   1   1   1
# 2   1   1   1   0   0   0

All we need to do is to select correct columns from df1 for each row of df1, and my first line does exactly that.

Upvotes: 1

Related Questions