Sarah,
i = 1
while i > 0 {
print("Thank you")
i = i + 1
}
---
Richard Sherman
> On Mar 22, 2014, at 8:06 PM, Sarah Goslee <sarah.gos...@gmail.com> wrote:
>
> Hi Richard,
>
> ?if
> ?ifelse
> ?subset
> ?[
>
> depending on the specific operation. See inline.
>
> Given a data frame tdf with x, y, and a (or with vectors creating a
> data frame using):
> tdf <- data.frame(x=x, y=y, a=a)
>
>> On Sat, Mar 22, 2014 at 10:21 PM, Richard Sherman <rss....@gmail.com> wrote:
>> Hi all,
>>
>> A simple question, new-ish to R, coming from Stata, and I yes I've looked at
>> great length and not found ...
>>
>> In Stata I might write (with * in place of #)
>>
>> # regress y on x in the set of observations where a==1
>> reg y x if a==1
>
> lm(y ~ x, data=subset(tdf, a==1))
>
>>
>> # descriptives on x where a==1
>> su x if a==1
>
> summary(subset(tdf, a==1)$x)
> or
> summary(tdf[tdf$a == 1,])
> or if they are vectors
> summary(x[a==1])
>
>>
>> # generate a logical depending on the value of a variable
>> gen z = (a == 1)
>
> z <- a==1
>
>>
>> # or likewise for a numeric
>> gen x = y if a == 1
>
> I'm not sure what this one is supposed to do. What's x if a isn't 1?
>
> But those examples should be enough to get you started, especially if
> you also read the Intro to R that comes with your R installation.
> Subsetting is a very basic operation, as you say, and pretty much
> every intro/tutorial I've read talks about it. I'm not sure where you
> looked in your extensive searching.
>
> Sarah
>
>>
>> # show the values of a variable based on the value of another variable
>> di y if a ~= .
>>
>> # generate a logical based on missing-ness of a variable
>> gen w = (a~=.)
>>
>> or any of many similar operations conditional on the value of a variable.
>>
>> Believe it or not this is a big obstacle to learning R.
>>
>> ---
>> Richard Sherman
>
>
> --
> Sarah Goslee
> http://www.functionaldiversity.org
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