[R] Stripchart: way to get different colour for each group

[johannes rara]

It seems that it is not possible to color points that way using
stripchart. I found a workaround which solved the problem:

stripchart(values ~ ind,
        data=mydata.stack,
        vertical=T,
        at=c(1.25, 1.75),
        pch=15,
        col="white")
points(rep(1.25, nrow(mydata)), mydata$val1, col=ifelse(mydata$group
== 0, "red", "yellow"), pch=15)
points(rep(1.75, nrow(mydata)), mydata$val2, col=ifelse(mydata$group
== 0, "red", "yellow"), pch=15)

Thanks,

- J

2009/12/1 johannes rara <johannesraja at gmail.com>:
> I was probably too vague. I meant that the group variable descirbes
> the group (eg. different individuals) and val1 and val2 are just two
> variables measured from eg. individual.
>
>> mydata
>   val1 val2 group
> 1   1.1  4.2     0
> 2   3.2  5.3     1
> 3   4.1  3.4     0
> 4   2.5  2.6     1
> 5   6.2  5.3     0
> 6   5.3  6.2     1
> 7   4.5  7.7     0
> 8   2.2  4.8     1
> 9   4.7  3.4     0
> 10  2.7  2.1     1
>
>
> So, I want to color the points of those groups using different colour.
>
> - J
>
> 2009/12/1 David Winsemius <dwinsemius at comcast.net>:
>>
>> On Dec 1, 2009, at 12:42 AM, johannes rara wrote:
>>
>>> Hi,
>>>
>>> Is there a way to get different colour based on group when plotting
>>> stripchart?
>>>
>>> mydata <- data.frame(val1 = c(1.1, 3.2, 4.1, 2.5, 6.2, 5.3, 4.5, 2.2,
>>> 4.7, 2.7), val2 = c(4.2, 5.3, 3.4, 2.6, 5.3, 6.2, 7.7, 4.8, 3.4, 2.1),
>>> group = rep(0:1, 5))
>>> mydata.stack <- stack(mydata, select=-group)
>>>
>>> stripchart(values ~ ind,
>>>         data=mydata.stack,
>>>         vertical=T,
>>>         at=c(1.25, 1.75),
>>>         pch=15,
>>>         col="red")
>>>
>>> I would like to get different colour for the two groups (based on
>>> group variable). I tried something like
>>>
>>> stripchart(values ~ ind,
>>>         data=mydata.stack,
>>>         vertical=T,
>>>         at=c(1.25, 1.75),
>>>         pch=15,
>>>         col=c("red", "yeallow")[mydata$group])
>>
>> Doesn't this work?
>>
>> stripchart(values ~ ind,
>>         data=mydata.stack,
>>         vertical=T,
>>         at=c(1.25, 1.75),
>>         pch=15,
>>         col=c("red", "yellow") )
>>
>> I would not think that mydata$group would be "in sync" with the dataset that
>> you are passing to stripchart.
>>
>> --
>> David
>>
>> David Winsemius, MD
>> Heritage Laboratories
>> West Hartford, CT
>>
>>
>