[R] calling in inverted commas

Frede Aakmann Tøgersen frtog at vestas.com
Sat Apr 12 09:24:51 CEST 2014 

Hi

Sigh I'm getting a headache seeing ugly formatted R code. Arun, your code is almost unreadable. Have a look at e.g. http://yihui.name/en/2010/04/formatr-farewell-to-ugly-r-code/

Now to the substantial. Why not use the sprintf() function for formatting the url instead of the more involved approach using several gsub and regular expressions that not many people (including myself) easily understand.

## here is a small example using sprintf(), see ?sprintf
## %s is format specifier for string
exampleStr <- "west=%s&north=%s&east=%s&south=%s"

sprintf(exampleStr, 1, 2, 3, 4)
## > [1] "west=1&north=2&east=3&south=4"

## since % is used in format specification then if a literal % is needed in the string as here
## where you have e.g. %2F01% then escape those % with a %, i.e. % becomes %% in the string
## I have done that in urlPattern:
urlPattern <- "http://disc2.nascom.nasa.gov/daac-bin/Giovanni/tovas/Giovanni_cgi.pl?west=%s&north=%s&east=%s&south=%s&params=0|3B42_V7&plot_type=Time+Plot&byr=1998&bmo=01&bdy=1&eyr=2007&emo=12&edy=31&begin_date=1998%%2F01%%2F01&end_date=2014%%2F01%%2F31&cbar=cdyn&cmin=&cmax=&yaxis=ydyn&ymin=&ymax=&yint=&ascres=0.25x0.25&global_cfg=tovas.global.cfg.pl&instance_id=TRMM_V7&prod_id=3B42_daily&action=ASCII+Output"

## some coordinates
df2 <- data.frame(Longitude = c(68.25, 68.75, 69.25), Latitude = c(24.75, 25.25, 25.75)) 

fileDestination <- c("C:/Temp")
fileNames <- paste("precip", df2[,1], df2[,2], sep = "_")
fileNames <- paste(fileNames, "txt", sep = ".")
files <- file.path(fileDestination, fileNames)

for (i in 1:nrow(df2)){
    queryUrl <- sprintf(urlPattern, df2[i, 1], df2[i, 2], df2[i, 1], df2[i, 2])
    download.file(queryUrl, files[i])
}

## import data in first file
precip <- read.table(files[1], skip = 4, header = TRUE, na.strings = "-9999.9",
                     sep = "", check.names = FALSE, stringsAsFactors = FALSE)

head(precip)


Here is another way using the url() function instead of download.file()

## Escaping the trouble with saving and reading files one can also do it this way
## having the dataframes in a named list
precipList <- vector("list", nrow(df2))
names(precipList) <- fileNames

for (i in 1:nrow(df2)){
    queryUrl <- sprintf(urlPattern, df2[i, 1], df2[i, 2], df2[i, 1], df2[i, 2])
    u <- url(queryUrl, open = "r")
    precipList[[i]] <- read.table(u, skip = 4, header = TRUE, na.strings = "-9999.9",
                     sep = "", check.names = FALSE, stringsAsFactors = FALSE)
    close(u)
}

str(precipList)

Have a nice day.


Yours sincerely / Med venlig hilsen


Frede Aakmann Tøgersen
Specialist, M.Sc., Ph.D.
Plant Performance & Modeling

Technology & Service Solutions
T +45 9730 5135
M +45 2547 6050
frtog at vestas.com
http://www.vestas.com

Company reg. name: Vestas Wind Systems A/S
This e-mail is subject to our e-mail disclaimer statement.
Please refer to www.vestas.com/legal/notice
If you have received this e-mail in error please contact the sender. 


> -----Original Message-----
> From: r-help-bounces at r-project.org [mailto:r-help-bounces at r-project.org]
> On Behalf Of arun
> Sent: 12. april 2014 07:16
> To: r-help at r-project.org
> Subject: Re: [R] calling in inverted commas
> 
> Hi,
> I noticed some special characters after sending.
> It should be:
> toreplace <- gsub(".*\\.pl\\?(west\\=.*south=.*)\\&params.*","\\1",Url1)
> end <- gsub(".*south=.*(\\&params.*)","\\1",Url1)
> 
> 
> A.K.
> 
> 
> On Saturday, April 12, 2014 1:06 AM, arun <smartpink111 at yahoo.com>
> wrote:
> HI,
> 
> Not sure if this helps:
> df2 <- data.frame(Col1=c(68.25, 68.75, 69.25), Col2=c(24.75, 25.25, 25.75))
> 
> 
> Url1 <- "http://disc2.nascom.nasa.gov/daac-
> bin/Giovanni/tovas/Giovanni_cgi.pl?west=68.25&north=24.75&east=68.25&s
> outh=24.75¶ms=0%7C3B42_V7&plot_type=Time+Plot&byr=1998&bmo=01&
> bdy=1&eyr=2007&emo=12&edy=31&begin_date=1998%2F01%2F01&end_da
> te=2014%2F01%2F31&cbar=cdyn&cmin=&cmax=&yaxis=ydyn&ymin=&ymax
> =&yint=&ascres=0.25x0.25&global_cfg=tovas.global.cfg.pl&instance_id=TRM
> M_V7∏_id=3B42_daily&action=ASCII+Output"
> 
> 
> toreplace <- gsub(".*\\.pl\\?(west\\=.*south=.*)\\¶ms.*","\\1",Url1)
> begin <- gsub("(.*\\.pl\\?).*","\\1",Url1)
> end <- gsub(".*south=.*(\\¶ms.*)","\\1",Url1)
> 
> vec2 <- strsplit(toreplace,"&")[[1]]
> 
> ##replace ".csv" with ".txt" and use write.table() if you need as text files.
> 
> 
> lapply(seq_len(nrow(df2)),function(i) { val1 <-
> as.vector(rep(unlist(df2[i,]),2));replaced <-
> do.call(paste,list(lapply(seq_along(vec2),function(i) gsub("[-
> +]?(\\d*[.])?\\d+",val1[i],vec2[i])),collapse="&")); UrlNew <-
> paste0(begin,replaced,end); res <-
> read.csv(UrlNew,header=TRUE,stringsAsFactors=FALSE,skip=4,sep="",check.
> names=FALSE);
> write.csv(res,file=paste0("file_",paste(val1[1:2],collapse="_"),".csv"),row.na
> mes=FALSE,quote=FALSE)})
> 
> sapply(list.files(pattern="file_"),function(x) {x1 <-
> read.csv(x,header=TRUE,stringsAsFactors=FALSE,check.names=FALSE);
> dim(x1)[1]})
> #file_68.25_24.75.csv file_68.75_25.25.csv file_69.25_25.75.csv
> 
> #                3652                 3652                 3652
> 
> ### reading the downloaded file
> 
> lapply(list.files(pattern="file_"),function(x) {x1 <-
> read.csv(x,header=TRUE,stringsAsFactors=FALSE,check.names=FALSE);
> x1[5:7,]})
> 
> #[[1]]
> 
> #  Time(year:month:day) AccRain
> 
> #5           1998:01:05   0.000
> 
> #6           1998:01:06   0.000
> #7           1998:01:07   0.984
> 
> #
> 
> #[[2]]
> 
> #  Time(year:month:day) AccRain
> #5           1998:01:05  0.0000
> #6           1998:01:06  0.0925
> #7           1998:01:07  0.2643
> #
> #[[3]]
> 
> #  Time(year:month:day) AccRain
> #5           1998:01:05  0.0000
> #6           1998:01:06  0.7043
> 
> #7           1998:01:07  0.5340
> 
> 
> 
> A.K.
> 
> 
> On Friday, April 11, 2014 2:38 PM, eliza botto <eliza_botto at hotmail.com>
> wrote:
> Dear useRs,
> Here are three steps for downloading a file from a certain website in R. Here
> you see that in "URL" command
> (west=68.25&north=24.75&east=68.25&south=24.75) are actually the first
> and second column values of 1st row of a matrix called df2 (300 rows and 2
> columns). more precisely, df2[1,][1]=68.25, df2[1,][2]=24.75.
> Is there a way that I can make a loop so that remaining rows and columns get
> inculcated in the link as such and then get saved at the desired mentioned
> location in 300 different text files?
> URL<-("http://disc2.nascom.nasa.gov/daac-
> bin/Giovanni/tovas/Giovanni_cgi.pl?west=68.25&north=24.75&east=68.25&s
> outh=24.75¶ms=0%7C3B42_V7&plot_type=Time+Plot&byr=1998&bmo=01&
> bdy=1&eyr=2007&emo=12&edy=31&begin_date=1998%2F01%2F01&end_da
> te=2014%2F01%2F31&cbar=cdyn&cmin=&cmax=&yaxis=ydyn&ymin=&ymax
> =&yint=&ascres=0.25x0.25&global_cfg=tovas.global.cfg.pl&instance_id=TRM
> M_V7∏_id=3B42_daily&action=ASCII+Output")
> 
> destfile <- "C:\\Users\\Eliza\\Desktop\\AA\\love.txt"
> download.file(URL, destfile)
> 
> Any suggestion?
> Thankyou very much in advance,
> Eliza
>     [[alternative HTML version deleted]]
> 
> ______________________________________________
> R-help at r-project.org mailing list
> 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 at r-project.org mailing list
> 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.

More information about the R-help mailing list