On 11 August 2015 at 02:09, Glenn Schultz wrote: | All, | Is my function just plain wrong or is it just programming style? I use connections because SODA (software for data analysis) recommends using connections when working with serialized files.
Nothing wrong with connections. Many of us use them. | First, after researching the use of return() - following Joshua's comment and others I found a post on SO regarding return(). http://stackoverflow.com/questions/11738823/explicitly-calling-return-in-a-function-or-not Let's try once more. The function foo() foo <- function() { x <- 2 return(x) x <- 3 } will return what value? Ie what does 'print(foo())' show? | Second, Hadley's point regarding the use of RDS in gz function being a little strange. Following the help files the function is fashioned after the following which I found in R help files: IIRC what Hadley was trying to say what you do _not_ need to compress before inserting into a rds file as the rds file format compresses by default. In other words compression comes for free, and effortlessly so. Hth, Dirk | ## Less convenient ways to restore the object | ## which demonstrate compatibility with unserialize() | con <- gzfile("women.rds", "rb") | identical(unserialize(con), women) | close(con) | con <- gzfile("women.rds", "rb") | wm <- readBin(con, "raw", n = 1e4) # size is a guess | close(con) | identical(unserialize(wm), women) | | With respect to the first, I understand why my function would be considered "buggy" - that can be fixed. It is the case, generally speaking, one does not need return() when programming in R; it is a functional language. However, some use return() and one finds return(value) in the R help files. Is it a strict no-no to use return()? | | With respect to the second, The function can be refactored and reduced to readRDS(). My question, is using gz file overkill or just plain wrong? | What is considered "best practice"? | | -Glenn | | | On Aug 09, 2015, at 09:04 AM, Joshua Ulrich <josh.m.ulr...@gmail.com> wrote: | | On Sun, Aug 9, 2015 at 8:59 AM, Glenn Schultz <glennmschu...@me.com> wrote: | Hi All, | | I use connections to open and close data folders needed by my package. | After each function closes I get the following warnings (depending on the | connection that has been opened). | | 10: closing unused connection 3 | (/Library/Frameworks/R.framework/Versions/3.2/Resources/library/BondLab/BondData/bondlabMBS4.rds) | | Below is the connection function that is related to the above warning: | | #------------------------------------------------------------------------------------ | #' A connection function to BondData calling MBS cusps | #' | #' Opens a connection to the BondData folder to call MBS cusip data | #' @param MBS.id A character string the MBS.id or cusip number current | MBS.id is supported | #' @export | MBS <- function(MBS.id = "character"){ | MBS.Conn <- gzfile(description = paste(system.file(package | = "BondLab"), | "/BondData/", MBS.id, ".rds", sep = ""), open | = "rb") | MBS <- readRDS(MBS.Conn) | return(MBS) | close.connection(MBS.Conn) | } | | I have googled this warning and it seems to be triggered when a function | terminates and the connection is open. But, I think the connection function | closes the connection once the object is returned. What am I doing wrong? | | Your call to return() exits the function, so the close.connection() | call is never evaluated. Considering using on.exit() to close the | connection, since it will close the connection regardless of how the | function exits (e.g. because of an error). | | -Glenn | ______________________________________________ | R-package-devel@r-project.org mailing list | https://stat.ethz.ch/mailman/listinfo/r-package-devel | | | | -- | Joshua Ulrich | about.me/joshuaulrich | FOSS Trading | http://www.fosstrading.com | ______________________________________________ | R-package-devel@r-project.org mailing list | https://stat.ethz.ch/mailman/listinfo/r-package-devel -- http://dirk.eddelbuettel.com | @eddelbuettel | e...@debian.org ______________________________________________ R-package-devel@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-package-devel
