sorry for the duplicate, but for some reason, the answer shown here doesn't work for me. I´ve checked and the data table I'm working with is of character nature.
That's my data table
> dt <- data.table(V1 = c("4", "1", "0", "3"), V2 = c("0/1", "0/1", "1/2", "3/4"))
> dt
V1 V2
1: 4 0/1
2: 1 0/1
3: 0 1/2
4: 3 3/4
> class(dt)
[1] "data.table" "data.frame"
> class(dt$V2)
[1] "character"
As you see I modeled the second column so as to have elements exclusively in fraction format. I want to have the second column in decimal format, the first column as a numeric rather than character & the final objective is to have the two columns summed up row-wise.
As I try turning it to decimal however it has no effect whatsoever on my dt - see it for yourselves
> FractionToDecimal <- function(x) {
+ eval(parse(text=as.character(x)))
+ x
+ }
> sapply(dt$V2, FractionToDecimal)
0/1 0/1 1/2 3/4
"0/1" "0/1" "1/2" "3/4"
> FractionToDecimal(dt$V2)
[1] "0/1" "0/1" "1/2" "3/4"
The other approach I used, also doesn't work out
> dt %>% mutate(V2 = eval(parse(text = V2)))
V1 V2
1 4 0.75
2 1 0.75
3 0 0.75
4 3 0.75
It just repeats the wrong result all over.
Does someone know where the problem lies?
If someone also knows how to have both columns turned into numeric/integer format afterward, it would also be of help!!
Thank you!!
Your function works but you are not changing x in the function and returning an unchanged x.
So either return output of eval + parse directly
FractionToDecimal <- function(x) eval(parse(text=x))
sapply(dt$V2, FractionToDecimal, USE.NAMES = FALSE)
#[1] 0.00 0.00 0.50 0.75
Or store the result in x and return the changed x.
FractionToDecimal <- function(x) {
x <- eval(parse(text=x))
x
}
sapply(dt$V2, FractionToDecimal, USE.NAMES = FALSE)
#[1] 0.00 0.00 0.50 0.75