[R] lapply and boxplots with variable names

[Phil Spector]

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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