looping and subsetting in ggplot

Question

I'm having difficulties subsetting data within a loop to create multiple ggplots. The objective is to create a plot for each unique value of id. The problem I believe is in fill = reason which I believe needs subsetting too.

## Calendar plot loop
id.calendar <- function(daily, na.rm = TRUE, ...){

myid <- unique(daily$id)

for (i in seq_along(myid)) { 

calendar <-
ggplot(subset(dat, dat$id==myid[i]),
       aes(monthweek, weekdayf, fill = reason)) +
  geom_tile(colour = "grey80") +
  facet_grid(year~monthf)

print(calendar)
}
}

Error: Insufficient values in manual scale. 9 needed but only 6 provided.

dat$id is a string (though it could be converted to numeric). I read somewhere in this forum that subsetting is best done outside of ggplot. Regardless, I need the loop to be fast.

[How to make a great R reproducible example?](http://stackoverflow.com/questions/5963269) — zx8754, Mar 16 '16 at 07:14
I think this `for (i in seq_along(myid))` should be `for (i in myid)` ? seq_along gives 1:n numbers, e.g.: `seq_along(letters[1:3])` — zx8754, Mar 16 '16 at 07:15
Apologies for not including a reproducible example (I normally do that). — Thomas Speidel, Mar 16 '16 at 14:09

score 1 · Accepted Answer · answered Mar 16 '16 at 08:56

Guessing a bit here as there is no data, but I think this is what you want. Note that I arranged the different id plots underneath each other using arrangeGrob:

library(ggplot2)
library(grid)
library(gridExtra)

id.calendar <- function(daily,na.rm = TRUE,...) {

    myid <- unique(daily$id)

    gpl <- list()
    n <- length(myid)
    for(i in 1:n) {

        df <-subset(dat,dat$id == myid[i])
        title <- sprintf("ID %s has %d elements",myid[i],nrow(df))
        gpl[[i]] <-  ggplot(df,
            aes(monthweek,weekdayf,fill = reason)) +
            geom_tile(colour = "grey80") +
            facet_grid(year ~ monthf) +
            labs(title=title)
    }
    glst <<- gpl
    calendar <- arrangeGrob(grobs=gpl,nrow=n)
    grid.draw(calendar)
}

# fake up some data
n <- 50
id <- sample(c("A","B","C"),n,replace=T)
mw <- sample(1:4,n,replace=T)
wd <- sample(0:6,n,replace=T)
mm <- sample(1:12,n,replace=T)
year <- sample(2011:2014,n,replace=T)
reason <- sample(c("Reason1","Reason2","Reason3","Reason4"),n,replace=T)
daily <- data.frame(id=id)
dat <- data.frame(id=id,monthweek=mw,year=year,monthf=mm,weekdayf=wd,reason=reason)

id.calendar(daily)

Yielding:

looping and subsetting in ggplot

1 Answers1