Create variables in data frame with for loop

Question

I have a main data frame (mydata) and two secondary ones (df1, df2) such as follows:

x <- c(1, 2, 3, 4, 5)
y <- c(5, 4, 3, 2, 1)
mydata <- data.frame(x)
df1 <- data.frame(y)
df2 <- data.frame(y)
df2$y <- y+1 #This way, the columns in the df have the same name but different values.

I want to create new columns in mydata based on a formula with the variables in df1 and df2 like this:

mydata$new1 <- mydata$x*df1$y
mydata$new2 <- mydata$x*df2$y

Is there a way I can do this with a for loop? This is what I had in mind:

for (i in 2) {
  mydata$paste0("new", i) <- mydata$x*dfpaste0(i)$y
}

arg0naut91 · Accepted Answer · 2018-11-10 17:39:07Z

2

Something along the lines of:

for (i in 1:2) {

  mydata[[as.symbol(paste0('new', i))]] <- mydata$x*get(paste0("df", i))$y

}

answered Nov 10, 2018 at 17:39

arg0naut91

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Comments

akrun · Accepted Answer · 2018-11-10 21:38:23Z

0

We could also use mget to get all the object values in a list and multiply with the concerned vector

mydata[paste0("new", 1:2)] <- mydata$x * data.frame(mget(paste0("df", 1:2)))

answered Nov 10, 2018 at 21:38

akrun

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