[R] for loops?
Barry Rowlingson
B.Rowlingson at lancaster.ac.uk
Mon Feb 2 16:18:07 CET 2004
Catherine Stein wrote:
> How can one use a for loop (or something similar) in R? As I type in each
> line, I get syntax errors... I'm just confused how much to type in at each
> ">" prompt.
>
Have you read help("for") (you need to quote 'for' here to avoid a
syntax error!)?
If you'd shown us exactly what you'd typed we could probably help
better. Suppose you want to loop from 1 to 10 and print it. You can do
the following, where '>' is the R prompt (dont type it):
> for(i in 1:10)print(i)
- ie all on one line
> for(i in 1:10){print(i)}
- with curly brackets
> for(i in 1:10)
+ print(i)
- where '+' is the continuation prompt (dont type it) - R gives you
this when it realises you havent written a complete expression yet.
> for(i in 1:10) {
+ print(i)
+ }
- curly brackets enclose as many expressions as you like inside the
loop.
> for(i in 1:10)
+ { print(i)
+ }
- curly brackets anywhere. R works it out.
You can even do, and I didn't think this would work...
> for(i in
+ 1:10)
+ {print(i)}
So in short, I cant get it to give a syntax error :) What are you
doing? What version of R, and what platform?
Baz
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