Plotting Simple Data in R - r

Question

I have a comma separated file named foo.csv containing the following data:
scale, serial, spawn, for, worker
5, 0.000178, 0.000288, 0.000292, 0.000300
10, 0.156986, 0.297926, 0.064509, 0.066297
12, 2.658998, 6.059502, 0.912733, 0.923606
15, 188.023411, 719.463264, 164.111459, 161.687982
I essentially have two questions:
1) How do I plot the first column (x-axis) versus the second column (y-axis)? I'm trying this (from reading this site):
data <- read.table("foo.csv", header=T,sep=",")
attach(data)
scale <- data[1]
serial <- data[2]
plot(scale,serial)
But I get this error back:
Error in stripchart.default(x1, ...) : invalid plotting method
Any idea what I'm doing wrong? A quick Google search reveals someone else with the same problem but no relevant answer. UPDATE: It turns out it works fine if I skip the two assignment statements in the middle. Any idea why this is?
The second question follows pretty easily after the first:
2) How do I plot the first column (x-axis) versus all the other columns on the y-axis? I presume it's pretty easy once I get around the first problem I'm running into, but am just a bit new to R so I'm still wrapping my head around it.

Answer 1

You don't need the two lines:
scale <- data[1]
serial <- data[2]
as scale and serial are already set from the headers in the read.table.
Also scale <- data[1] creates an element from a data.frame
data[1]
1 5
2 10
3 12
4 15
whereas scale from the read.table is a vector
5 10 12 15
and the plot(scale, serial) function expects vector rather than a data.frame, so you just need to do
plot(scale, serial)
One approach to plotting the other columns of data on the y-axis:
plot(scale,serial, ylab="")
par(new=TRUE)
plot(scale,spawn,axes=F, ylab="", type="b")
par(new=TRUE)
plot(scale,for., axes=F, ylab="", type="b")
par(new=TRUE)
plot(scale,worker,axes=F, ylab="", type="b")
There are probably better ways of doing this, but that is beyond my current R knowledge....

Answer 2

In your example,
plot(scale, serial)
won't work because scale and serial are both data frames, e.g.
class(scale)
[1] "data.frame"
You could try the following and use points(), once the plot has been generated, to plot the remaining columns. Note, I used the ylim parameter in plot to accommodate the range in the third column.
data <- read.csv('foo.csv', header=T)
plot(data$scale, data$serial, ylim=c(0,750))
points(data$scale, data$spawn, col='red')
points(data$scale, data$for., col='green')
points(data$scale, data$worker, col='blue')

Answer 3

I'm new in R, but if you want to draw scale vs. all other columns in one plot, easy and with some elegance :) for printing or presentation, you may use Prof. Hadley Wickham's packages ggplot2 & reshape.
Installation:
install.packages(“ggplot2”,dep=T)
install.packages(“reshape”,dep=T)
Drawing your example:
library(ggplot2)
library(reshape)
#read data
data = read.table("foo.csv", header=T,sep=",")
#melt data “scale vs. all”
data2=melt(data,id=c("scale"))
data2
scale variable value
1 5 serial 0.000178
2 10 serial 0.156986
3 12 serial 2.658998
4 15 serial 188.023411
5 5 spawn 0.000288
6 10 spawn 0.297926
7 12 spawn 6.059502
8 15 spawn 719.463264
9 5 for. 0.000292
10 10 for. 0.064509
11 12 for. 0.912733
12 15 for. 164.111459
13 5 worker 0.000300
14 10 worker 0.066297
15 12 worker 0.923606
16 15 worker 161.687982
#draw all variables at once as line with different linetypes
qplot(scale,value,data=data2,geom="line",linetype=variable)
You could also use points (geom=”points”), choose different colours or shapes for different variables dots (colours=variable or shape=variable), adjust axis, set individual options for every line etc.
Link to online documentation.

Answer 4

I am far from being an R expert, but I think you need a data.frame:
plot(data.frame(data[1],data[2]))
It does at least plot something on my R setup!
Following advice in luapyad's answer, I came up with this. I renamed the header "scale":
scaling, serial, spawn, for, worker
5, 0.000178, 0.000288, 0.000292, 0.000300
10, 0.156986, 0.297926, 0.064509, 0.066297
12, 2.658998, 6.059502, 0.912733, 0.923606
15, 188.023411, 719.463264, 164.111459, 161.687982
then:
foo <- read.table("foo.csv", header=T,sep=",")
attach(foo)
plot( scaling, serial );

Answer 5

Try this:
data <- read.csv('foo.csv')
plot(serial ~ scale, data)
dev.new()
plot(spawn ~ scale, data)
dev.new()
plot(for. ~ scale, data)
dev.new()
plot(worker ~ scale, data)

Answer 6

There is a simple-r way of plotting it:
https://code.google.com/p/simple-r/
Using that script, you just have to type:
r -cdps, -k1:2 foo.csv
To get the plot you want. Put it in the verbose mode (-v) to see the corresponding R script.

Answer 7

data <- read.table(...)
plot(data$scale,data$serial)