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]]
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