[R] Is there an variant of apply() that does not return anything?

[Peng Yu]

I want to use both the name and the content. Although, I could do the
following thing.

for(x in names(List)) {
  do some thing with x
  do some thing with List[[x]]
}

However, I'd prefer something like the following if R offers such
functionality. But it seems not.

for(x in List) {
  do something with the name of x
  do something with x
}

On Fri, Nov 20, 2009 at 4:35 PM, Jorge Ivan Velez
<jorgeivanvelez at gmail.com> wrote:
> If I understood correctly
> for(x in names(List)) print(x)
> should do what you asked.
> HTH, Jorge
>
> On Thu, Nov 19, 2009 at 5:31 PM, Peng Yu <> wrote:
>>
>> On Thu, Nov 19, 2009 at 4:27 PM, Marc Schwartz <marc_schwartz at me.com>
>> wrote:
>> > On Nov 20, 2009, at 10:21 AM, Peng Yu wrote:
>> >
>> >> There are a few version of apply() (e.g., lapply(), sapply()). I'm
>> >> wondering if there is one that does not return anything but just
>> >> silently apply a function to the list argument.
>> >>
>> >> For example, the plot function is applied to each element in 'alist'.
>> >> It is redundant to return anything from apply.
>> >>
>> >> apply(alist,function(x){ plot each element of alist})
>> >
>> >
>> >
>> > Just use a for() loop. If you are plotting things, the performance
>> > bottleneck is not going to be in the loop.
>> >
>> > Sometimes, we get too anal about avoiding for() loops.
>>
>> Is there a way to get the name of the list in the loop body?
>>
>> > List=list(a='c',b='x',e='q')
>> > for(x in List) { print(x) }
>> [1] "c"
>> [1] "x"
>> [1] "q"
>>
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>
>