On 13/12/2010 12:56 PM, Arthur Charpentier wrote:
sorry... localization is a string of characters
for instance
localization =
paste("http://www.resultsfromtennis.com/",year,"/atp/",city,".html",sep="";)
where year is 2006 and city can be "wimbledon"
hence here, since the page
"http://www.resultsfromtennis.com/2007/atp/wimbledon.html"; does exist, I
can get the tables inside
but
"http://www.resultsfromtennis.com/1977/atp/shertogenbosch.html";
does not exist... is there a way to detect that the html page does not
exist ?
If you try to read it and get an error, you will know there's a problem.
For example,
x <- "http://cran.r-project.ogr"; # has a typo
con <- url(x)
html <- readLines(con)
This should produce an error, but might give you a junk page if your DNS
provider substitutes for it. You can catch the error using
html <- try(readLines(con), silent=TRUE)
if (inherits(html, "try-error")) cat("Error!")
Duncan Murdoch
2010/12/13 Duncan Murdoch <murdoch.dun...@gmail.com
<mailto:murdoch.dun...@gmail.com>>
On 13/12/2010 12:36 PM, Arthur Charpentier wrote:
I was wondering if there was a function like "does connection
exists" ?
See ?showConnections.
I am currently using loops to build up a database, and I have either
B = getConnection(localization)
Error in getConnection(localization) : there is no connection
-2147483648
In addition: Warning message:
In getConnection(localization) : NAs introduced by coercion
Where did the localization variable come from? getConnection is
pretty rarely used.
or
B = scan(localization)
Error in file(file, "r") : cannot open the connection
In addition: Warning message:
In file(file, "r") : cannot open: HTTP status was '404 Not Found'
is there a way to test where localization is an html page, or
not ? and to
say that if localization does exist, then scan it ?
What's your definition of an html page? Testing for valid html is hard.
Duncan Murdoch
______________________________________________
R-devel@r-project.org mailing list
https://stat.ethz.ch/mailman/listinfo/r-devel
