[R] how to get a value from a list (using paste function)?

[Jessica Streicher]

Well for one, if ever someone looks at your code, cvtest[[lambda.rule]] is much easier to read and understand than
eval(parse(text=paste0("cvtest$",lambda.rule)))


On 27.12.2012, at 11:44, Heramb Gadgil wrote:

> I am not sure why "Never ever!"
> 
> Can you please elaborate. What are the negatives about the method
> 
> Warm Regards,
> Heramb M. Gadgil
> 
> 
> On Thu, Dec 27, 2012 at 3:50 PM, Uwe Ligges <ligges at statistik.tu-dortmund.de
>> wrote:
> 
>> 
>> 
>> On 27.12.2012 08:09, Heramb Gadgil wrote:
>> 
>>> eval(parse(text=paste0("**cvtest$",lambda.rule)))
>>> 
>> 
>> No, never ever!
>> 
>> There is an R idiom made for it:
>> 
>> cvtest[[lambda.rule]]
>> 
>> Uwe Ligges
>> 
>> 
>> 
>> 
>> 
>> 
>> 
>> I hope this works.
>>> 
>>> On Wed, Dec 19, 2012 at 12:57 AM, Thomas Stewart
>>> <tgs.public.mail at gmail.com>**wrote:
>>> 
>>> Soyeon-
>>>> 
>>>> A possible solution:
>>>> 
>>>> get(lambda.rule,envir=**list2env(cvtest))
>>>> 
>>>> 
>>>> On Tue, Dec 18, 2012 at 12:34 PM, Soyeon Kim <yunni0731 at gmail.com>
>>>> wrote:
>>>> 
>>>> Dear my R friends,
>>>>> 
>>>>> I want to get a number from a list using paste function.
>>>>> In my example,
>>>>> lambda.rule <- "lambda.1se"
>>>>> cvtest is a list (result from cv.glmnet)
>>>>> and
>>>>> cvtest$lambda.1se
>>>>> [1] 1.308973
>>>>> 
>>>>> I want to call the value using paste function.
>>>>> I used get function but there was an error.
>>>>> test <-  get(paste("cvtest$",lambda.**rule, sep=""))
>>>>> Error in get(paste("cvtest$", lambda.rule, sep = "")) :
>>>>>   object 'cvtest$lambda.1se' not found
>>>>> 
>>>>> Do you guys know how to solve this issue?
>>>>> 
>>>>> Thank you so much in advance and merry Christmas!
>>>>> 
>>>>> Soyeon
>>>>> 
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>>>>> 
>>>>> 
>>>>> 
>>>>> 
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>>>> 
>>>> 
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> 
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> 
> ______________________________________________
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