grep(pattern, textVector) returns of the integer indices of the elements of textVector that match the pattern. E.g., > grep("T", c("One","Two","Three","Four")) [1] 2 3
The '&' operator naturally operates on logical vectors of the same length (If you give it numbers it silently converts 0 to FALSE and other numbers to TRUE.) The two don't fit together. You could use grepl(), which returns a logical vector the length of textVector, as in grepl(p1,v1) & grepl(p2,v2) to figure which entries in the table have v1 matching p1 and v2 matching p2. Or, you could use intersect(grep(p1,v1), grep(p2,v2)) if you want to stick with integer indices. By the way, the eval(parse(text=paste(...))) business is a good way to make hard-to-read code and hard-to-read means hard-to-fix. Just write out the expression. > paste( + "dt2 <- dt[", "grep('", par.fund, "', fund) & ", + "grep('", par.func, "', func) & grep('", par.obj, "', obj)", + ", sum(amount), by=c('code', 'year')]" , sep="") [1] "dt2 <- dt[grep('^1.E$', fund) & grep('^1.....$', func) & grep('^...$', obj), sum(amount), by=c('code', 'year')]" Bill Dunlap Spotfire, TIBCO Software wdunlap tibco.com > -----Original Message----- > From: r-help-boun...@r-project.org [mailto:r-help-boun...@r-project.org] On > Behalf > Of Bush, Daniel P. DPI > Sent: Thursday, March 14, 2013 2:43 PM > To: 'r-help@r-project.org' > Subject: [R] Grep with wildcards across multiple columns > > I have a fairly large data set with six variables set up like the following > dummy: > > # Create fake data > df <- data.frame(code = c(rep(1001, 8), rep(1002, 8)), > year = rep(c(rep(2011, 4), rep(2012, 4)), 2), > fund = rep(c("10E", "10E", "10E", "27E"), 4), > func = rep(c("110000", "122000", "214000", "158000"), 4), > obj = rep("100", 16), > amount = round(rnorm(16, 50000, 10000))) > > What I would like to do is sum the amount variable by code and year, > filtering rows using > different wildcard searches in each of three columns: "1?E" in fund, > "1??????" in func, > and "???" in obj. I'm OK turning these into regular expressions: > > # Set parameters > par.fund <- "10E"; par.func <- "100000"; par.obj <- "000" > par.fund <- glob2rx(gsub("0", "?", par.fund)) > par.func <- glob2rx(gsub("0", "?", par.func)) > par.obj <- glob2rx(gsub("0", "?", par.obj)) > > The problem occurs when I try to apply multiple greps across columns. I'd > prefer to use > data.table since it's so much faster than plyr and I have 159 different sets > of parameters > to run through, but I get the same error setting it up either way: > > # Doesn't work > library(data.table) > dt <- data.table(df) > eval(parse(text=paste( > "dt2 <- dt[", "grep('", par.fund, "', fund) & ", > "grep('", par.func, "', func) & grep('", par.obj, "', obj)", > ", sum(amount), by=c('code', 'year')]" , sep=""))) > # Warning message: > # In grep("^1.E$", fund) & grep("^1.....$", func) : > # longer object length is not a multiple of shorter object length > > # Also doesn't work > library(plyr) > eval(parse(text=paste( > "df2 <- ddply(df[grep('", par.fund, "', df$fund) & ", > "grep('", par.func, "', df$func) & grep('", par.obj, "', df$obj), ]", > ", .(code, year), summarize, amount = sum(amount))" , sep=""))) > # Warning message: > # In grep("^1.E$", df$fund) & grep("^1.....$", df$func) : > # longer object length is not a multiple of shorter object length > > Clearly, the problem is how I'm trying to combine greps in subsetting rows, > but I haven't > been able to find a solution that works. Any thoughts-preferably something > that works > with data.table? > > DB > > Daniel Bush > School Finance Consultant > School Financial Services > Wisconsin Department of Public Instruction > PO Box 7841 | Madison, WI 53707-7841 > daniel.bush -at- dpi.wi.gov | sfs.dpi.wi.gov > Ph: 608-267-9212 | Fax: 608-266-2840 > > > > > [[alternative HTML version deleted]] > > ______________________________________________ > R-help@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@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.