Add header and first column-CodePudding

I have two data frames such as df1 and df2.

df1 = id a1 a2 a3 a4 
     21 .2 .4 .1 .7
     22 .4 .5 .1 .2
df2 = .2 .4 .2 .3
      .3 .5 .2 .1

How to add the header such as "a1, a2, a3 and a4" and first column (id, 21, 22) of df1 in df2?

CodePudding user response：

This will add the first column of df1 to df2-

df2 <- cbind(df1$id, df2)

Then, you can use this command and it will set the headers of df2 same as headers of df1

colnames(df2) <- colnames(df1)

CodePudding user response：

Another solution with the use the setNames function:

 df2 <- setNames(df1, c("id","a1","a2", "a3","a4"))

or this to change column name by colnames function.

colnames(df2)[1]<-paste("id")  
colnames(df2)[2]<-paste("a1")  
colnames(df2)[3]<-paste("a2")  
colnames(df2)[4]<-paste("a3")

Sample data:

df1 = data.frame("id"=c(21,22), "a1"=c(.2,.4 ), "a2"=c(.4,.5), "a3"=c(.1,.1), " a4"=c(.7,.2))

df2= data.frame ("id2"=c(.2,.3), "a1_2"=c(.4,.5), "a2_2"=c(.2,.2), "a3_2"=c(.3,.1))