[R] axes labeling

[Jim Lemon]

On 12/21/2012 07:12 AM, Sam Steingold wrote:
>> * David L Carlson<qpneyfba at gnzh.rqh>  [2012-12-20 13:58:00 -0600]:
>>
>> It is possible, but only by using axis() since you can specify axis breaks
>> in a plot command, but not the labels. You can ignore most of the axis()
>> options so the commands are pretty simple:
>>
>> plot(x=c(1, 1000000), y=c(1, 1000000), xlab="x", ylab="y",
>>       xaxt="n", yaxt="n", las=2)
>> pos<- c(0, 200000, 400000, 600000, 800000, 1000000)
>> lbl<- c("0", "200k", "400k", "600k", "800k", "1000k")
>> axis(1, pos, lbl)
>> axis(2, pos, lbl)
>
> That's what I meant when I said "too much control".
> I am happy with the way R selects positions.
> All I want is a say in the way R formats those positions.
>
> Think in terms of 1000000 being a variable.
> To use axis, I will need to write a map from variable range to axis tick
> positions first, and then sapply my formatting to the positions.
>
Hi Sam,
You can use the "pretty" function to get the default positions of the 
axis labels by passing the range of the values:

pretty(1:1000000)
[1] 0e+00 2e+05 4e+05 6e+05 8e+05 1e+06

Then you can pass these values to the axis function with your labels 
(0k, 200k, ...)

Jim