Hi everyone, Hi ggplot users in particular,
ggplot makes it very easy to plot things given their names when you
use it interactively (and therefore can provide the names of the
columns).
qplot(x,foo,data=A) where A has columns (x,y,foo,bar) for example
but I would like to use this from inside a function to which the name
of the column is given. I cannot find an elegant way to make this
work. Here are my attempts:
#------------------------------------------------------------
library(ggplot2)
A = data.frame(x=rep(1:10,10), y=rep(1:10,each=10), u=runif(100),
v=rnorm(100))
# goal: extract values for y<=5 and plot them, either for u or v
foo1 <- function(uv="u")
{
# solution 1: do not use the data argument at all
# (forces the use of qplot, could be more elegant)
B = A[A$y<=5,]
qplot(B$x, B$y, fill=B[[uv]], geom="tile")
}
foo2 <- function(uv="u")
{
# solution 2: extract and rename the colums, then use the data argument
# (enables ggplot but could be shorter)
B = A[A$y<=5,c("x","y",uv)]
names(B)[3] = "value"
# rem: cannot use rename since rename(B,c(uv="value")) would not work
qplot(x, y, fill=value, data=B, geom="tile")
# or
# ggplot(B,aes(x=x,y=y,fill=value)) + geom_tile()
}
foo3 <- function(uv="u")
{
# solution 3: use the data argument and perform the extraction
directly in it
# (elegant and powerful but can't make it work)
ggplot(A[A$y<=5,c("x","y",uv)],aes(x=x,y=y,fill=???)) + geom_tile()
# or
ggplot(A[A$y<=5,],aes(x=x,y=y,fill=???)) + geom_tile()
# or ...
}
print(foo1("u"))
print(foo1("v"))
print(foo2("u"))
print(foo3("u"))
#------------------------------------------------------------
Any help in making foo3 work would be appreciated. Thanks in advance
for your expertise.
JiHO
---
http://jo.irisson.free.fr/
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