[R] Break during the recursion?
Duncan Murdoch
murdoch at stats.uwo.ca
Sun Jul 15 17:17:45 CEST 2007
On 15/07/2007 10:33 AM, Atte Tenkanen wrote:
>> On 15/07/2007 10:06 AM, Atte Tenkanen wrote:
>>> Hi,
>>>
>>> Is it possible to break using if-condition during the recursive
>> function?
>> You can do
>>
>> if (condition) return(value)
>>
>>> Here is a function which almost works. It is for inorder-tree-
>> walk.
>>> iotw<-function(v,i,Stack,Indexes) # input: a vector and the first
>> index (1), Stack=c(), Indexes=c().
>>> {
>>> print(Indexes)
>>> # if (sum(i)==0) break # Doesn't work...
>> if (sum(i)==0) return(NULL)
>>
>> should work.
>>
>> Duncan Murdoch
>
> Hmm - - - I'd like to save the Indexes-vector (in the example c(8,4,9,2,10,5,11,1,3)) and stop, when it is ready.
This seems more like a problem with the design of your function than a
question about R. I can't really help you with that, because your
description of the problem doesn't make sense to me. What does it mean
to do an inorder tree walk on something that isn't a tree?
Duncan Murdoch
>
> The results are enclosed to the end.
>
> Atte
>
>>>
>>> if (is.na(v[i])==FALSE & is.null(unlist(v[i]))==FALSE)
>>> {Stack=c(i,Stack); i=2*i; iotw(v,i,Stack,Indexes)}
>>> Indexes=c(Indexes,Stack[1])
>>> Stack=pop.stack(Stack)$vector
>>> Indexes=c(Indexes,Stack[1])
>>> i=2*Stack[1]+1
>>> Stack=pop.stack(Stack)$vector
>>> iotw(v,i,Stack,Indexes)
>>> }
>>>
>>>
>>>> v=c(`-`,`+`,1,`^`,`^`,NA,NA,"X",3,"X",2)
>>>> Stack=c()
>>>> Indexes=c()
>>>> iotw(v,1,Stack,Indexes)
>>> NULL
>>> NULL
>>> NULL
>>> NULL
>>> NULL
>>> [1] 8 4
>>> [1] 8 4
>>> [1] 8 4 9 2
>>> [1] 8 4 9 2
>>> [1] 8 4 9 2
>>> [1] 8 4 9 2 10 5
>>> [1] 8 4 9 2 10 5
>>> [1] 8 4 9 2 10 5 11 1
>>> [1] 8 4 9 2 10 5 11 1
>>> [1] 8 4 9 2 10 5 11 1 3
>>> Error in if (is.na(v[i]) == FALSE & is.null(unlist(v[i])) ==
>> FALSE) { :
>>> argument is of length zero
>>>
>>> Regards,
>>>
>>> Atte Tenkanen
>>> University of Turku, Finland
>>>
>
>
>> iotw(v,1,Stack,Indexes)
> NULL
> NULL
> NULL
> NULL
> NULL
> [1] 8 4
> [1] 8 4
> [1] 8 4 9 2
> [1] 8 4 9 2
> [1] 8 4 9 2
> [1] 8 4 9 2 10 5
> [1] 8 4 9 2 10 5
> [1] 8 4 9 2 10 5 11 1
> [1] 8 4 9 2 10 5 11 1
> [1] 8 4 9 2 10 5 11 1 3
> [1] 8 4 9 2 10 5 11 1 3
> [1] 8 4 9 2 10 5 11 1
> [1] 8 4 9 2 10 5 11 1
> [1] 8 4 9 2 10 5 11 1 3
> [1] 8 4 9 2 10 5 11 1 3
> [1] 8 4 9 2 10 5
> [1] 8 4 9 2 10 5
> [1] 8 4 9 2 10 5 11 1
> [1] 8 4 9 2 10 5 11 1
> [1] 8 4 9 2 10 5 11 1 3
> [1] 8 4 9 2 10 5 11 1 3
> [1] 8 4 9 2 10 5 11 1
> [1] 8 4 9 2 10 5 11 1
> [1] 8 4 9 2 10 5 11 1 3
> [1] 8 4 9 2 10 5 11 1 3
> [1] 8 4 9 2 5 1
> [1] 8 4 9 2 5 1
> [1] 8 4 9 2 5 1 3
> [1] 8 4 9 2 5 1 3
> [1] 8 4 9 2
> [1] 8 4 9 2
> [1] 8 4 9 2
> [1] 8 4 9 2 10 5
> [1] 8 4 9 2 10 5
> [1] 8 4 9 2 10 5 11 1
> [1] 8 4 9 2 10 5 11 1
> [1] 8 4 9 2 10 5 11 1 3
> [1] 8 4 9 2 10 5 11 1 3
> [1] 8 4 9 2 10 5 11 1
> [1] 8 4 9 2 10 5 11 1
> [1] 8 4 9 2 10 5 11 1 3
> [1] 8 4 9 2 10 5 11 1 3
> [1] 8 4 9 2 10 5
> [1] 8 4 9 2 10 5
> [1] 8 4 9 2 10 5 11 1
> [1] 8 4 9 2 10 5 11 1
> [1] 8 4 9 2 10 5 11 1 3
> [1] 8 4 9 2 10 5 11 1 3
> [1] 8 4 9 2 10 5 11 1
> [1] 8 4 9 2 10 5 11 1
> [1] 8 4 9 2 10 5 11 1 3
> [1] 8 4 9 2 10 5 11 1 3
> [1] 8 4 9 2 5 1
> [1] 8 4 9 2 5 1
> [1] 8 4 9 2 5 1 3
> [1] 8 4 9 2 5 1 3
> [1] 8 4
> [1] 8 4
> [1] 8 4 9 2
> [1] 8 4 9 2
> [1] 8 4 9 2
> [1] 8 4 9 2 10 5
> [1] 8 4 9 2 10 5
> [1] 8 4 9 2 10 5 11 1
> [1] 8 4 9 2 10 5 11 1
> [1] 8 4 9 2 10 5 11 1 3
> [1] 8 4 9 2 10 5 11 1 3
> [1] 8 4 9 2 10 5 11 1
> [1] 8 4 9 2 10 5 11 1
> [1] 8 4 9 2 10 5 11 1 3
> [1] 8 4 9 2 10 5 11 1 3
> [1] 8 4 9 2 10 5
> [1] 8 4 9 2 10 5
> [1] 8 4 9 2 10 5 11 1
> [1] 8 4 9 2 10 5 11 1
> [1] 8 4 9 2 10 5 11 1 3
> [1] 8 4 9 2 10 5 11 1 3
> [1] 8 4 9 2 10 5 11 1
> [1] 8 4 9 2 10 5 11 1
> [1] 8 4 9 2 10 5 11 1 3
> [1] 8 4 9 2 10 5 11 1 3
> [1] 8 4 9 2 5 1
> [1] 8 4 9 2 5 1
> [1] 8 4 9 2 5 1 3
> [1] 8 4 9 2 5 1 3
> [1] 8 4 9 2
> [1] 8 4 9 2
> [1] 8 4 9 2
> [1] 8 4 9 2 10 5
> [1] 8 4 9 2 10 5
> [1] 8 4 9 2 10 5 11 1
> [1] 8 4 9 2 10 5 11 1
> [1] 8 4 9 2 10 5 11 1 3
> [1] 8 4 9 2 10 5 11 1 3
> [1] 8 4 9 2 10 5 11 1
> [1] 8 4 9 2 10 5 11 1
> [1] 8 4 9 2 10 5 11 1 3
> [1] 8 4 9 2 10 5 11 1 3
> [1] 8 4 9 2 10 5
> [1] 8 4 9 2 10 5
> [1] 8 4 9 2 10 5 11 1
> [1] 8 4 9 2 10 5 11 1
> [1] 8 4 9 2 10 5 11 1 3
> [1] 8 4 9 2 10 5 11 1 3
> [1] 8 4 9 2 10 5 11 1
> [1] 8 4 9 2 10 5 11 1
> [1] 8 4 9 2 10 5 11 1 3
> [1] 8 4 9 2 10 5 11 1 3
> [1] 8 4 9 2 5 1
> [1] 8 4 9 2 5 1
> [1] 8 4 9 2 5 1 3
> [1] 8 4 9 2 5 1 3
> [1] 4 2
> [1] 4 2
> [1] 4 2
> [1] 4 2 10 5
> [1] 4 2 10 5
> [1] 4 2 10 5 11 1
> [1] 4 2 10 5 11 1
> [1] 4 2 10 5 11 1 3
> [1] 4 2 10 5 11 1 3
> [1] 4 2 10 5 11 1
> [1] 4 2 10 5 11 1
> [1] 4 2 10 5 11 1 3
> [1] 4 2 10 5 11 1 3
> [1] 4 2 10 5
> [1] 4 2 10 5
> [1] 4 2 10 5 11 1
> [1] 4 2 10 5 11 1
> [1] 4 2 10 5 11 1 3
> [1] 4 2 10 5 11 1 3
> [1] 4 2 10 5 11 1
> [1] 4 2 10 5 11 1
> [1] 4 2 10 5 11 1 3
> [1] 4 2 10 5 11 1 3
> [1] 4 2 5 1
> [1] 4 2 5 1
> [1] 4 2 5 1 3
> [1] 4 2 5 1 3
> [1] 2 1
> [1] 2 1
> [1] 2 1 3
> [1] 2 1 3
> [1] 1
> [1] 1
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