How to plot all the columns of a data frame in R

Question

The data frame has n columns and I would like to get n plots, one plot for each column.

I'm a newbie and I am not fluent in R, anyway I found two solutions.

The first one works but it does not print the column name (and I need them!):

data <- read.csv("sample.csv",header=T,sep=",")
for ( c in data ) plot( c, type="l" )

The second one works better because it prints the column name:

data <- read.csv("sample.csv",header=T,sep=",")
for ( i in seq(1,length( data ),1) ) plot(data[,i],ylab=names(data[i]),type="l")

Is there any better (from the R language point of view) solutions?

Answer 1

The ggplot2 package takes a little bit of learning, but the results look really nice, you get nice legends, plus many other nice features, all without having to write much code.

require(ggplot2)
require(reshape2)
df <- data.frame(time = 1:10,
                 a = cumsum(rnorm(10)),
                 b = cumsum(rnorm(10)),
                 c = cumsum(rnorm(10)))
df <- melt(df ,  id.vars = 'time', variable.name = 'series')

# plot on same grid, each series colored differently -- 
# good if the series have same scale
ggplot(df, aes(time,value)) + geom_line(aes(colour = series))

# or plot on different plots
ggplot(df, aes(time,value)) + geom_line() + facet_grid(series ~ .)