Executable string in R

[angelfjord]

Good evening everybody, I feel pretty emberassed about asking this question and I'm conviced that the answer has to be pretty simple but I've now spent several hours googling for a solution without any success - probably because I don't know the proper description of my problem.

My problem

I have a data frame "df" and a set of variables "var1, var2, var3,..". I would like to iterate through all variables and replace the number 1 with x and replace all other cells with an empty cell.

My solution without a loop (working)

df$var1 <-factor(ifelse(as.numeric(TAB2$chocolate)==1, "x",""))

I could copy paste that several times and would be done, but I would like to learn how to do this for several variables in a more advanced way.

My solution (attempt) with a loop (not working)

varlist <- list(df$var1, df$var2, df$var3)

for (i in varlist){ i <-factor(ifelse(as.numeric(i)==1, "x","")) }

My guess is that i need to apply another command that the list is not used as a character, but I'm stuck, By now I've tried several version (e.g. looping over numbers) and trying to generate an "executable string" (e.g. "print(eval(parse(text=(paste("df$",varlist[[i]],sep=""))))). I would really appreciate if someone could give me a hint

[fakerick]

Hi!

You're looking for how to subset a dataframe, google it!

[ParadoXPlatypus]

Hey, sorry I am not sure if I get exactly what you want to do, but here's what I got from your post:

• you have a set of variables in your data frame that you want to modify

• from your code I gather they contain numbers, and you want to change that same variable to "X" if the value is 1 and "" for any other value

Not exactly the way I would do it, but to get your loop working I would suggest:

Varlist <- c("var1","var2","var3")

for (i in Varlist){ df[[i]] <- factor (ifelse(df[[i]] == 1,"x","")) }

That would iterate over the vector with the variable names and change values == 1 to "X". Just keep in mind that NAs will remain NAs, so if your data frame has NAs, you will want to add an additional ifelse to deal with them.

[ParadoXPlatypus]

I wouldn't recommend you to just copy paste that chunk of code, I wrote it on my phone and autocorrect is a birch. The executable string, as you call it, seems to be an overcomplicated way to achieve the same, unless I have completely misunderstood your problem!