[R] x[0]: Can '0' be made an allowed index in R?

John Fox j|ox @end|ng |rom mcm@@ter@c@
Tue Apr 23 16:23:36 CEST 2024


Hello Peter,

Unless I too misunderstand your point, negative indices for removal do 
work with the Oarray package (though -0 doesn't work to remove the 0th 
element, since -0 == 0 -- perhaps what you meant):

 > library(Oarray)

 > v <- Oarray(1:10, offset=0)

 > v
[0,] [1,] [2,] [3,] [4,] [5,] [6,] [7,] [8,] [9,]
    1    2    3    4    5    6    7    8    9   10

 > dim(v)
[1] 10

 > v[-1]
[1]  1  3  4  5  6  7  8  9 10

 > v[-0]
[1] 1

Best,
  John

On 2024-04-23 9:03 a.m., Peter Dalgaard via R-help wrote:
> Caution: External email.
> 
> 
> Doesn't sound like you got the point. x[-1] normally removes the first element. With 0-based indices, this cannot work.
> 
> - pd
> 
>> On 22 Apr 2024, at 17:31 , Ebert,Timothy Aaron <tebert using ufl.edu> wrote:
>>
>> You could have negative indices. There are two ways to do this.
>> 1) provide a large offset.
>> Offset <- 30
>> for (i in -29 to 120) { print(df[i+Offset])}
>>
>>
>> 2) use absolute values if all indices are negative.
>> for (i in -200 to -1) {print(df[abs(i)])}
>>
>> Tim
>>
>>
>>
>> -----Original Message-----
>> From: R-help <r-help-bounces using r-project.org> On Behalf Of Peter Dalgaard via R-help
>> Sent: Monday, April 22, 2024 10:36 AM
>> To: Rolf Turner <rolfturner using posteo.net>
>> Cc: R help project <r-help using r-project.org>; Hans W <hwborchers using gmail.com>
>> Subject: Re: [R] x[0]: Can '0' be made an allowed index in R?
>>
>> [External Email]
>>
>> Heh. Did anyone bring up negative indices yet?
>>
>> -pd
>>
>>> On 22 Apr 2024, at 10:46 , Rolf Turner <rolfturner using posteo.net> wrote:
>>>
>>>
>>> See fortunes::fortune(36).
>>>
>>> cheers,
>>>
>>> Rolf Turner
>>>
>>> --
>>> Honorary Research Fellow
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>>> University of Auckland
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>>
>> --
>> Peter Dalgaard, Professor,
>> Center for Statistics, Copenhagen Business School Solbjerg Plads 3, 2000 Frederiksberg, Denmark
>> Phone: (+45)38153501
>> Office: A 4.23
>> Email: pd.mes using cbs.dk  Priv: PDalgd using gmail.com
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>> ______________________________________________
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> 
> --
> Peter Dalgaard, Professor,
> Center for Statistics, Copenhagen Business School
> Solbjerg Plads 3, 2000 Frederiksberg, Denmark
> Phone: (+45)38153501
> Office: A 4.23
> Email: pd.mes using cbs.dk  Priv: PDalgd using gmail.com
> 
> ______________________________________________
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