Sent from my phone. Please excuse my brevity.
On June 15, 2017 8:39:47 AM PDT, Huzefa Khalil <huzefa.khalil at umich.edu> wrote:
>Hi,
>
>Try
>
>> is.null(mylist[[1]])
>[1] TRUE
>
>Notice the double square brackets.
>
>From: ?`[`
>"The most important distinction between [, [[ and $ is that the [ can
>select more than one element whereas the other two select a single
>element."
>
>On Thu, Jun 15, 2017 at 11:33 AM, ce <zadig_1 at excite.com> wrote:
>> Hi
>>
>> I have a list :
>>
>> mylist <- list( a = NULL, b = 1, c = 2 )
>>
>>> mylist[1]
>> $a
>> NULL
>>
>>> is.null(mylist[1])
>> [1] FALSE
>>
>>> is.null(mylist$a)
>> [1] TRUE
>>
>> why? I need to use mylist[1]
>> ______________________________________________
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>> and provide commented, minimal, self-contained, reproducible code.