[R] is there any method to defer the execution of code in r?

[Jeff Newmiller]

Not when I click on that link.

On May 13, 2018 7:37:50 AM PDT, Rui Barradas <ruipbarradas using sapo.pt> wrote:
>Hello,
>
>I don't understand.
>
>It *is* the same question. Same code, same words. And same 'AKSHAY  M 
>KULKARNI' (the OP here) and 'AKshayKulkarni' (SO).
>
>Exactly the same.
>
>Rui Barradas
>
>On 5/13/2018 2:07 PM, Jeff Newmiller wrote:
>> I am puzzled by the use of the term "cross-posted" here... I don't
>see the OP or their question or any similar words from the question
>involved the the given link, though that link seems worth bringing it
>to the OP's attention.
>> 
>> But the function given in the question seems to have other problems:
>> 
>> A) The download.file function call puts its result in a different
>place than the read.csv reads data from. Unless the OP is manually
>moving files around with the  file browser in the background I don't
>see how this would ever work.
>> 
>> B) The file paths refer to C:/Users/user ... it would be highly
>unusual for there to be such a directory on any machine, so I am
>wondering how close any of this code is to what the OP actually did.
>> 
>> C) Reading the help page for download.file, it appears to behave like
>most functions in R... it does not return until the operation is
>complete. That is, the premise of the question seems flawed, and a
>truly reproducible example would be needed to convince me to go down
>the delay rabbit hole. The OP has been around this list long enough to
>know where to go to find out how to make a reproducible example.
>> 
>> 
>> On May 13, 2018 1:16:47 AM PDT, Rui Barradas <ruipbarradas using sapo.pt>
>wrote:
>>> Hello,
>>>
>>> This is cross posted from StackOverflow:
>>>
>>>
>https://stackoverflow.com/questions/50314015/is-there-any-method-to-defer-the-execution-of-code-in-r
>>>
>>> Cross posting is discouraged in r-help.
>>>
>>> Rui Barradas
>>>
>>> On 5/13/2018 8:59 AM, akshay kulkarni wrote:
>>>> dear members,
>>>>
>>>> I have created the following function to read a csv file from a
>given
>>> URL:
>>>>
>>>>       function(){
>>>>                               s <- 1;
>>>>
>>>>                               #first get the bhav copy
>>>>                               today <- c();ty <- c();tm <- c();tmu
><-
>>> c();td <- c();
>>>>
>>>>                              # get the URL first
>>>>                               today <- Sys.Date()
>>>>                               ty <- format(today, format = "%Y")
>>>>                               tm <- format(today, format = "%b")
>>>>                               tmu <- toupper(tm)
>>>>                               td <- format(today, format = "%d")
>>>>
>>>>              dynamic.URL <-
>>>
>paste("https://www.nseindia.com/content/historical/EQUITIES/",ty,"/",tmu,"/cm",td,tmu,ty,"bhav.csv.zip",
>>> sep = "")
>>>>              file.string <-
>>> paste("C:/Users/user/AppData/Local/Temp/cm",td,tmu,ty,"bhav.csv")
>>>>
>>>>                               download.file(dynamic.URL,
>>> "C:/Users/user/Desktop/bhav.csv.zip")
>>>>                               bhav.copy <- read.csv(file.string)
>>>>                               return(bhav.copy)
>>>>       }
>>>>
>>>> If I run the function, immediately it says that "file.string not
>>> found". But when I run it after some time(a few seconds), it
>executes
>>> normally. I think when `download.file` ecexecutes, it transfers
>control
>>> to `read.csv, `and it tries to load the file which is not yet
>properly
>>> saved. when I run it after some time, it tries to overwrite the
>>> existing file, which it cannot, and the `read.csv`properly loads the
>>> saved file.`
>>>>
>>>> I want the function to execute the first time I run it. Is there
>any
>>> way or a function to defer the action of `read.csv`until the file is
>>> properly saved? Something like this:
>>>>
>>>>       download.file(dynamic.URL,
>"C:/Users/user/Desktop/bhav.csv.zip")
>>>>                                   wait......
>>>>                                   bhav.copy <-
>read.csv(file.string)
>>>>
>>>> Ignore the fact that the destfile in download.file is different
>from
>>> file.string; it is due to function of my system (windows 7).
>>>>
>>>> Very many thanks for your time and effort...
>>>>
>>>> AKSHAY  M KULKARNI
>>>>
>>>>
>>>> 	[[alternative HTML version deleted]]
>>>>
>>>> ______________________________________________
>>>> R-help using r-project.org mailing list -- To UNSUBSCRIBE and more, see
>>>> https://stat.ethz.ch/mailman/listinfo/r-help
>>>> PLEASE do read the posting guide
>>> http://www.R-project.org/posting-guide.html
>>>> and provide commented, minimal, self-contained, reproducible code.
>>>>
>>>
>>> ______________________________________________
>>> R-help using r-project.org mailing list -- To UNSUBSCRIBE and more, see
>>> https://stat.ethz.ch/mailman/listinfo/r-help
>>> PLEASE do read the posting guide
>>> http://www.R-project.org/posting-guide.html
>>> and provide commented, minimal, self-contained, reproducible code.
>> 

-- 
Sent from my phone. Please excuse my brevity.