# Re: [R] use different symbols for frequency in a plot

From: Marc Schwartz (via MN) <mschwartz_at_mn.rr.com>
Date: Tue 09 Aug 2005 - 06:44:10 EST

On Mon, 2005-08-08 at 11:57 -0700, Kerry Bush wrote:
> suppose I have the following data
>
> x<-c(rep(.1,5),rep(.2,6),rep(.4,10),rep(.5,20))
> y<-c(rep(.5,3),rep(.6,8),rep(1.2,8),rep(2.5,18),rep(3,4))
>
> If I plot(x,y) in R, I will only get seven distinct
> points. What I want to do is to use different symbols
> to show the frequency at each point.
>
> e.g. if the frequncey is between 1 and 5, then I plot
> the point as a circle; if the frequency is between 6
> and 10, then I plot the point as a square; if the
> frequency is above 10, then I plot the point as a
> triangle.
>
> I am not sure how to do this in R. Can anybody help me?

You might want to review this recent post by Deepayan Sarkar:

with modest modification you can replace his example, which plots the frequencies with:

x <- c(rep(.1,5),rep(.2,6),rep(.4,10),rep(.5,20)) y <- c(rep(.5,3),rep(.6,8),rep(1.2,8),rep(2.5,18),rep(3,4))

temp <- data.frame(x, y)

foo <- subset(as.data.frame(table(temp)), Freq > 0)

> foo

x y Freq

```1  0.1 0.5    3
5  0.1 0.6    2
6  0.2 0.6    6
11 0.4 1.2    8
15 0.4 2.5    2
16 0.5 2.5   16
20 0.5   3    4

```

# Use cut() to create the bins and specify the plotting symbols # for each bin, which are the 'label' values foo\$sym <- with(foo, cut(Freq, c(0, 5, 10, Inf),

```                         labels = c(21, 22, 24)))

```

# convert 'foo' to all numeric from factors above for plotting foo <- apply(foo, 2, function(x) as.numeric(as.character(x)))

> foo

x y Freq sym

```1  0.1 0.5    3  21
5  0.1 0.6    2  21
6  0.2 0.6    6  22
11 0.4 1.2    8  22
15 0.4 2.5    2  21
16 0.5 2.5   16  24
20 0.5   3    4  21

```

# Now do the plot. Keep in mind that 'foo' is now # a matrix, rather than a data frame
plot(foo[, "x"], foo[, "y"], pch = foo[, "sym"])

HTH, Marc Schwartz

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