[R] save conditions in a list

[Christof Kluß]

Hi Rui Barradas

thank you very much, that's what I searched for

result <- lapply(conds, fun, DF) works, if

day <- DF$day
val <- DF$val

Thanks
Christof




Am 02-07-2012 20:44, schrieb Rui Barradas:
> Hello,
> 
> I'm not sure if this is what you want.
> 
> 
> #-------------- Make up a dataset
> set.seed(1)
> n <- 1e2
> DF <- data.frame(year=2010 + sample(3, n, TRUE),
>         day=sample(365, n, TRUE),
>         val=sample(100, n, TRUE))
> 
> a = "day > 100"; b = "val < 50"; c = "year == 2012"
> conds <- list(a=a, b=b, c=c)
> 
> #-------------- This does it
> fun <- function(condition, x){
>     f <- function(){}
>     if(class(x) == "matrix") x <- data.frame(x)
>     if(class(x) == "data.frame")
>         body(f) <- with(x, parse(text=condition))
>     else
>         body(f) <- parse(text=condition)
>     f()
> }
> 
> #-------------- Test the function
> year <- DF$year # See if it works with vectors
> fun(b, year)    # Must throw error
> fun(c, year)    # Should work
> 
> # And now with data.frames
> result <- lapply(conds, fun, DF)
> 
> Reduce(`&`, result) # combine the results
> Reduce(`|`, result) #
> 
> 
> Hope this helps,
> 
> Rui Barradas
> 
> Em 02-07-2012 18:04, Christof Kluß escreveu:
>> Hi
>>
>> how would you save conditions like
>>
>> a = "day > 100"; b = "val < 50"; c = "year == 2012"
>>
>> in a list? I like to have variables like "day", "val", "year" and a list
>> of conditions list(a,b,c). Then I want to check if a & b & c is true or
>> if a | b | c is true or similar things.
>>
>> Greetings
>> Christof
>>
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>