R help - Nov 2009 - What is the best way to delete strings in a string list that that match certain pattern?

On Fri, Nov 6, 2009 at 3:05 AM, Diez B. Roggisch <deets at nospam.web.de>
wrote:
> Peng Yu schrieb:
>>
>> Suppose I have a list of strings, A. I want to compute the list (call
>> it B) of strings that are elements of A but doesn't match a regex.
I
>> could use a for loop to do so. In a functional language, there is way
>> to do so without using the for loop.
>
> Nonsense. For processing over each element, you have to loop over them,
> either with or without growing a call-stack at the same time.
>
> FP languages can optimize away the stack-frame-growth (tail recursion) -
but
> this isn't reducing complexity in any way.
>
> So use a loop, either directly, or using a list-comprehension.
What is a list-comprehension?

On Fri, 6 Nov 2009, Peng Yu wrote:
> On Fri, Nov 6, 2009 at 3:05 AM, Diez B. Roggisch <deets at
nospam.web.de> wrote:
>> Peng Yu schrieb:
>>>
>>> Suppose I have a list of strings, A. I want to compute the list
(call
>>> it B) of strings that are elements of A but doesn't match a
regex. I
>>> could use a for loop to do so. In a functional language, there is
way
>>> to do so without using the for loop.
>>
>> Nonsense. For processing over each element, you have to loop over them,
>> either with or without growing a call-stack at the same time.
>>
>> FP languages can optimize away the stack-frame-growth (tail recursion)
- but
>> this isn't reducing complexity in any way.
>>
>> So use a loop, either directly, or using a list-comprehension.
>
> What is a list-comprehension?

 	http://lmgtfy.com/?q=list+comprehension

>
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Charles C. Berry                            (858) 534-2098
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