Re-using Gabor's suggestion from yesterday, I think the regex incantation gsub("[^[:digit:].]+"," ",x)
also will do, where x is a your vector of strings. It says to replace runs of everything but digits and . with a single space. > x [1] "this Item costs 3.32 Dollars or maybe 10.00 cents" > gsub("[^[:digit:].]+"," ",x) [1] " 3.32 10.00 " You can then "pipe" this through a textConnection to convert it to numeric: > scan(textConnection(gsub("[^[:digit:].]+"," ",x))) Read 2 items [1] 3.32 10.00 Bert Gunter Genentech Nonclinical Biostatisics -----Original Message----- From: r-help-boun...@r-project.org [mailto:r-help-boun...@r-project.org] On Behalf Of Steve Lianoglou Sent: Wednesday, August 26, 2009 3:49 PM To: Martin Batholdy Cc: r-help@r-project.org Subject: Re: [R] find numbers in a line with letters Hi, On Aug 26, 2009, at 6:38 PM, Martin Batholdy wrote: > hi, > > is there an easy way to extract numbers from a string? > > for example I have; > "this Item costs 3.32 Dollars" > > is there an easy way to extract the 3.32 as a number? Regular expressions to the rescue? Perhaps you'll need to fine tune it, but see here: R> gregexpr("(\\d+(\\.\\d+)?)", "this Item costs 3.32 Dollars", perl=T) [[1]] [1] 17 attr(,"match.length") [1] 4 R> gregexpr("(\\d+(\\.\\d+)?)", "this Item costs 3.32 Dollars, that item costs 10.12 dollars", perl=T) [[1]] [1] 17 47 attr(,"match.length") [1] 4 5 R> gregexpr("(\\d+(\\.\\d+)?)", "this Item costs 3.32 Dollars, that item costs 10 dollars even, ", perl=T) [[1]] [1] 17 47 attr(,"match.length") [1] 4 2 R> gregexpr("(\\d+(\\.\\d+)?)", "this one is free ", perl=T) [[1]] [1] -1 attr(,"match.length") [1] -1 HTH, -steve -- Steve Lianoglou Graduate Student: Computational Systems Biology | Memorial Sloan-Kettering Cancer Center | Weill Medical College of Cornell University Contact Info: http://cbio.mskcc.org/~lianos/contact ______________________________________________ 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.