[R] qplot and for loops

[Joshua Wiley]

Hi,

You actually did the loop correctly.  The problem is that the graphs
were created very quickly so you only see the last one.  One way
around this is to make R wait for user input.  You can turn this on
and off for a particular device using:

par(ask = TRUE)

See ?par for details on this.

To create the various files in a for loop, you actually do not need
this.  You should be able to get by with something like:

png(filename = "Graph%03d.png")
for(i in 1:4){
  qplot(x[i]<-mydata[,i])
}
dev.off()

Hope this helps!

Josh

On Tue, Jul 12, 2011 at 12:21 PM, wwreith <reith_william at bah.com> wrote:
> I have 4 columns and 56 rows of made up data that I want to plot as a series
> of bar graphs. The idea is to create one bar graph for each of the 4 columns
> using a for loop. I tried the following command in RStudio and when I type x
> in the console I get just the 4th graph instead of all four graphs. I did
> not define what x is before hand. I was not sure what it would be. Any
> suggestions on how you would properly define x?
>
> for(i in 1:4){
> qplot(x[i]<-mydata[,i])
> }
>
> The headers of the columns are Trial.1 Trial.2 Trial.3 and Trial.4. Also
> note that I can easily make any of the four graphs by
>
> i=1 or i=2, etc.
> qplot(x<-mydata[,i])
>
> I just need to figure out how to make it loop correctly. The ultimate goal
> would also be to save these graphs to my computer with automatically
> generated file names. Something like test graph1.png, test graph2.png, etc.
>
> Thanks For The Help!
>
> --
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>
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-- 
Joshua Wiley
Ph.D. Student, Health Psychology
University of California, Los Angeles
https://joshuawiley.com/