Today we see how to set up multiple graphs on the same page. We use the syntax `par(mfrow=(A,B))`

, where `A`

refers to the number of rows and `B`

to the number of columns (and where each cell will hold a single graph). This syntax sets up a plotting environment of `A`

rows and `B`

columns.

First we create four vectors, all of the same length.

`X <- c(1, 2, 3, 4, 5, 6, 7)`

`Y1 <- c(2, 4, 5, 7, 12, 14, 16)`

`Y2 <- c(3, 6, 7, 8, 9, 11, 12)`

`Y3 <- c(1, 7, 3, 2, 2, 7, 9)`

Now we set up a plotting environment of two rows and three columns (in order to hold six graphs), using `par(mfrow())`

`par(mfrow=c(2,3))`

Now we plot six graphs on the same plotting environment. We use the `plot()`

command six times in succession, each time graphing one of the `Y`

vectors against the `X`

vector.

`plot(X,Y1, pch = 1)`

plot(X,Y2, pch = 2)

plot(X,Y3, pch = 3)

plot(X,Y1, pch = 4)

plot(X,Y2, pch = 15)

plot(X,Y3, pch = 16)

Out plot plot looks like this:

That wasnâ€™t so hard! In Blog 22 we will look at further plotting techniques in R.

See you later!

David

#### Annex: R codes used

[code lang="r"]

# Create four vectors of the same length.

X <- c(1, 2, 3, 4, 5, 6, 7)

Y1 <- c(2, 4, 5, 7, 12, 14, 16)

Y2 <- c(3, 6, 7, 8, 9, 11, 12)

Y3 <- c(1, 7, 3, 2, 2, 7, 9)

# Set up multiple graphs (2 x 3) on the same page.

par(mfrow=c(2,3))

# Create six scatterplots.

plot(X,Y1, pch = 1)

plot(X,Y2, pch = 2)

plot(X,Y3, pch = 3)

plot(X,Y1, pch = 4)

plot(X,Y2, pch = 15)

plot(X,Y3, pch = 16)

[/code]