[R] lapply and boxplots with variable names

[Shawn Morrison]

Many thanks Phil, that does help.

If I could ask a follow-up, how do I put each plot in its own device 
window? Right now, all I get is the boxplot for var2 (var1 gets 
overwritten?). I tried putting quartz() before the boxplot command but 
got an error message.

Cheers,
Shawn

On 22/06/10 11:13 AM, Phil Spector wrote:
> Shawn -
>    Does this example help?  (Please don't use cbind when creating
> a data frame, since it first creates a matrix, which means everything
> must be of the same mode.)
>
>> var1 = rnorm(1000)
>> var2 = rnorm(1000)
>> TimePeriod = rep((LETTERS[1:4]), 250)
>> my.data = data.frame(var1,var2,TimePeriod)
>> lapply(names(my.data)[1:2],
> +        function(y)boxplot(formula(paste(y,'TimePeriod',sep='~')),
> +        main=y,data=my.data))
>
>
>                     - Phil Spector
>                      Statistical Computing Facility
>                      Department of Statistics
>                      UC Berkeley
>                      spector at stat.berkeley.edu
>
>
> On Tue, 22 Jun 2010, Shawn Morrison wrote:
>
>> Hi all,
>>
>> I have a dataset with several variables, each of which is a separate 
>> column. For each variable, I want to produce a boxplot and include 
>> the name of the variable (ie, column name) on each plot.
>>
>> I have included a sample dataset below. Can someone tell me where I 
>> am going wrong?
>>
>> Thank you for your help,
>> Shawn Morrison
>>
>> # Generate a sample dataset
>> var1 = rnorm(1000)
>> var2 = rnorm(1000)
>> TimePeriod = rep((LETTERS[1:4]), 250)
>>
>> my.data = as.data.frame(cbind(var1, var2, TimePeriod)); summary(my.data)
>> attach(my.data)
>>
>> # Create box plots for var1 and var2 using TimePeriod on the x-axis
>> lapply(my.data[,1:2], function(y) {
>>    boxplot(y~TimePeriod,
>>                main = y
>>                data = my.data)
>>    })
>>
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