[R] How to take out the content of character string

Henrique Dallazuanna wwwhsd at gmail.com
Thu Mar 11 01:47:35 CET 2010


On Wed, Mar 10, 2010 at 7:50 PM, Thomas Lumley <tlumley at u.washington.edu> wrote:
> On Wed, 10 Mar 2010, baptiste auguie wrote:
>
>> Hi,
>>
>> it's generally considered a bad practice but try this,
>>
>> eval(parse(text=AA))
>>
>> library(fortunes)
>> fortune(106)
>>
>> HTH,
>>
>> baptiste
>>
>> On 10 March 2010 07:46, jq81 <jingqian81 at gmail.com> wrote:
>>>
>>> My question is represented by the following example.
>>>
>>> For example, I have a character string a, which is defined as
>>>
>>> AA="list(x=1, y=2)"
>>>
>>> I want to take out the content of AA by using some function, so that I
>>> can
>>> obtain the following expression automatically.
>>>
>>> list(x=1, y=2)
>>>
>
> This is the situation where it isn't considered bad practice.  If someone
> hands you a string with code in it, the only way to parse it is with
> parse().

I think that Is there another way:

source(textConnection(AA))$value
closeAllConnections()

> The problem with eval(parse()) is when people use it to do macro processing
> or other things that are much better done with expressions.
>
>    -thomas
>
> Thomas Lumley                   Assoc. Professor, Biostatistics
> tlumley at u.washington.edu        University of Washington, Seattle
>
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>



-- 
Henrique Dallazuanna
Curitiba-Paraná-Brasil
25° 25' 40" S 49° 16' 22" O



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