# [R] [FORGED] custom function gives unexpected result - for me

Jeff Newmiller jdnewm|| @end|ng |rom dcn@d@v|@@c@@u@
Sat Apr 18 02:11:40 CEST 2020

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On April 17, 2020 4:26:19 PM PDT, Rolf Turner <r.turner using auckland.ac.nz> wrote:
>
>
>precedence".) If you assign rn <- 3, then 1:rn-1 is:
>
>[1] 0 1 2
>
>The "-" operator is applied *after*  the ":" operator.
>
>You want 1:(rn-1) which gives
>
>[1] 1 2
>
>and the desired result.
>
>cheers,
>
>Rolf Turner
>
>On 18/04/20 7:55 am, Monica Palaseanu-Lovejoy wrote:
>> Hi,
>>
>> I wrote a relatively simple function. If i run the code inside the
>function
>> line by line i am getting the result i was expecting, but if i run
>the
>> function, i get a different result.
>>
>> The function:
>>
>> grr1 <- function(rn) {
>> r.up <- c()
>> for (i in 1:rn-1) {
>> if (i%%2==0) ru <- seq(1,i) else ru <- seq(i,1)
>> r.up <- c(r.up, ru)
>> }
>> return(r.up)
>> }
>>
>> So, if rn is 3 for example i would expect to get 1 1 2
>>
>> grr1(3)
>> [1] 1 0 1 1 2
>>
>> If i run it line by line inside the function:
>> r.up <- c()
>>> r.up
>> NULL
>>
>> i=1
>> if (i%%2==0) ru <- seq(1,i) else ru <- seq(i,1)
>>> ru
>> [1] 1
>>
>> r.up <- c(r.up, ru)
>> r.up
>> [1] 1
>>
>> i=2
>> if (i%%2==0) ru <- seq(1,i) else ru <- seq(i,1)
>> ru
>> [1] 1 2
>> r.up <- c(r.up, ru)
>>> r.up
>> [1] 1 1 2
>>
>> So - i am getting the result i am expecting. From where the 1 0
>before what
>> i expect as a result comes from? I am sure i am doing some very basic
>> error, but it seems i cannot figure it out.
>>
>> I run R x64  3.2.6. I know it is not the latest version, but it
>should not
>> give me unexpected results because of that i would think.
>>
>> sessionInfo()
>> R version 3.6.2 (2019-12-12)
>> Platform: x86_64-w64-mingw32/x64 (64-bit)
>> Running under: Windows 10 x64 (build 17763)
>>
>> Matrix products: default
>>
>> locale:
>> [1] LC_COLLATE=English_United States.1252
>> [2] LC_CTYPE=English_United States.1252
>> [3] LC_MONETARY=English_United States.1252
>> [4] LC_NUMERIC=C
>> [5] LC_TIME=English_United States.1252
>>
>> attached base packages:
>> [1] stats     graphics  grDevices utils     datasets  methods   base
>>
>> loaded via a namespace (and not attached):
>> [1] compiler_3.6.2
>>
>> Thanks,
>> Monica
>
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