[R] Split data frame and create a new column

[Rui Barradas]

Hello,

I don't know if this is general purpose but try


x <- scan(what = "character", text="
L1o3maxG10
L1o3P10
L2o3G10
noxP10
pm25S_01
comeanS_03
noxP_04")

fun <- function(x){
     r1 <- unlist(strsplit(x, "L[[:digit:]]+|G|P|S"))
     r1 <- r1[nchar(r1) != 0]
     r1 <- r1[rep(c(TRUE, FALSE), length(r1)/2)]
     r1 <- unlist(strsplit(r1, "max|mean"))
     r1 <- r1[nchar(r1) != 0]

     r2 <- integer(length(x))
     w2 <- grep("L[[:digit:]]+", x)
     re2 <- regexpr("L[[:digit:]]+", x)
     re2 <- unlist(strsplit(regmatches(x, re2), "L"))
     re2 <- re2[nchar(re2) != 0]
     r2[w2] <- re2
     w2 <- grep("G_|P_|S_", x)
     re2 <- regmatches(x, regexpr("(G_|P_|S_)[[:digit:]]+", x))
     re2 <- unlist(strsplit(re2, "G_|P_|S_"))
     re2 <- re2[nchar(re2) != 0]
     r2[w2] <- re2

     r3 <- regmatches(x, regexpr("G|P|S", x))

     data.frame(r1, r2, r3)
}

fun(x)


Hope this helps,

Rui Barradas
Em 16-11-2012 00:05, Zlatan escreveu:
> I need to split a data frame into 3 columns. The column I want to split
> contains indices of lag (prefix L1 or L2 and suffix 01, 03, 04), station
> name (shown in the sample data as capitalized G, P and S) and pollutant
> name. Names with no “L” prefix or 01/04 suffix are lag 0. Lag 01 is average
> of lag 0 and 1, and 04 is average of 0 to 4 days. How can one do that in R?
> I will ignore the other components( e.g. 10 , max or mean)
>
>
>
> Current stand
>
> L1o3maxG10
> L1o3P10
> L2o3G10
> noxP10
> pm25S_01
> comeanS_03
> noxP_04
>
> What I want to get :
>
> pollutant  Lag	station
> o3	1	G
> o3	1	P
> o3	2	G
> nox	0	P
> Pm25	01	S
> co	03	S
> nox	04	P
>
>
> Thanks
>
>
>
>
> --
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