Nested loop or equivalent - r

Question

I am trying to make a nested loop, I start with a simple loop and I would like make the same with differents data frames;
This work fine:
set.seed(123)
df1= data.frame(date= 1:10,
vartre=rnorm(10, 30, 4),
varpre=rnorm(10, 10, 5))
var=names(df1)
for(x in var ) {
plot(df1$date,df1[,x], type="l", main=x)
}
Now, I would like make the same with differents df´s, I tried to do with a nested loop but this dont work, example:
df2= data.frame(date= 1:10,
varkyt=rnorm(10, 100, 40),
varkdr=rnorm(10, 50, 5))
df3= data.frame(date= 1:10,
varwer=rnorm(10, 300, 400),
varpou=rnorm(10, 1000, 500))
dfs=c("df1", "df2", "df3")
for(i in dfs) {
var=names(i)
for(x in var ) {
plot(i$date,i[,x], type="l", main=paste(i,x)))
}
}
Thanks in advance

Answer 1

We can use lapply to loop over the list (mget -returns the list of data.frame from the string identifiers) and plot
out <- lapply(mget(dfs), function(dat) {
var <- names(dat)[-1]
lapply(var, function(x) plot(dat$date, dat[,x], type = "l",
main = x))
})
If we need to save it in a folder
path <- "path/to/folder/"
lapply(mget(dfs), function(dat) {
var <- names(dat)[-1]
lapply(var, function(x) {
png(filename=paste(path, "grafico", x,".png"))
plot(dat$date, dat[,x], type = "l",
main = x)
dev.off()
}
)
})