Plotting multiple lines from a data frame in R

Question

I am building an R function to plot a few lines from a data table, I don't understand why this is not working?

data = read.table(path, header=TRUE);
plot(data$noop);
lines(data$noop, col="blue");
lines(data$plus, col="green");

I am reading the data from a file I has which is formatted like this:

 noop         plus         mins
 33.3         33.3         33.3
 30.0         40.0         30.0
 25.0         50.0         25.0

This is the minimal representation of the dataset, which contains more headers and more data points. So each of the rows of this data set reflects a sample taken at a given time. So my objective is to read this data in from the file, and then plot each column as a series of points connected by lines of different color.

The approach I am using currently is only plotting 1 line, and not multiple lines.

Can you share your data table (or some representative sample)? — David Alber, Oct 27 '11 at 06:36
Check this [Frequently Unread Suggestion](http://stackoverflow.com/q/5963269/709529) for how to create a reproducible example. — Nick Sabbe, Oct 27 '11 at 08:01

score 19 · Accepted Answer · edited Dec 28 '12 at 12:59

19

Have a look at the ggplot2 package

library(ggplot2)
library(reshape)
data <- data.frame(time = seq(0, 23), noob = rnorm(24), plus = runif(24), extra = rpois(24, lambda = 1))
Molten <- melt(data, id.vars = "time")
ggplot(Molten, aes(x = time, y = value, colour = variable)) + geom_line()

enter image description here

edited Dec 28 '12 at 12:59

Henrik K

1,051
1
15
34

answered Oct 27 '11 at 08:52

Thierry

18,049
5
48
66

Have a look at http://had.co.nz/ggplot2/ You'll find many examples of graphs and the corresponding code – Thierry Oct 28 '11 at 07:49

score 11 · Answer 2 · answered Oct 27 '11 at 11:21

Or with base:

data <- data.frame(time = seq(0, 23), noob = rnorm(24), plus = runif(24), extra = rpois(24, lambda = 1))
plot(extra ~ time, 
  data = data, 
  type = "l", 
  ylim = c(min(data[ ,-1]), max(data[ ,-1])),
  ylab = "value")
lines(data$time, data$plus, col = "steelblue")
lines(data$time, data$noob, col = "pink")

score 4 · Answer 3 · answered Mar 29 '13 at 18:11

4

You don't need to load any package of for or apply, just simply use the matplot function built in R... Each column of a table will be a line in your graph (or symbols if you prefer).

answered Mar 29 '13 at 18:11

Cristian

41
1

Plotting multiple lines from a data frame in R

3 Answers3

Linked