Jun Shen
2016-Sep-05 04:06 UTC
[R] element wise pattern recognition and string substitution
Dear list,
I have a vector of strings that cannot be described by one pattern. So
let's say I construct a vector of patterns in the same length as the vector
of strings, can I do the element wise pattern recognition and string
substitution.
For example,
pattern1 <- "([^.]*)\\.([^.]*\\.[^.]*)\\.(.*)"
pattern2 <- "([^.]*)\\.([^.]*)\\.(.*)"
patterns <- c(pattern1,pattern2)
strings <- c('TX.WT.CUT.mean','mg.tx.cv')
Say I want to extract "WT.CUT" from the first string and
"tx" from the
second string. If I do
sub(patterns, '\\2', strings), only the first pattern will be used.
looping the patterns doesn't work the way I want. Appreciate any comments.
Thanks.
Jun
[[alternative HTML version deleted]]
Jeff Newmiller
2016-Sep-05 04:30 UTC
[R] element wise pattern recognition and string substitution
Your opening assertion is false. Provide a reproducible example and someone will demonstrate. -- Sent from my phone. Please excuse my brevity. On September 4, 2016 9:06:59 PM PDT, Jun Shen <jun.shen.ut at gmail.com> wrote:>Dear list, > >I have a vector of strings that cannot be described by one pattern. So >let's say I construct a vector of patterns in the same length as the >vector >of strings, can I do the element wise pattern recognition and string >substitution. > >For example, > >pattern1 <- "([^.]*)\\.([^.]*\\.[^.]*)\\.(.*)" >pattern2 <- "([^.]*)\\.([^.]*)\\.(.*)" > >patterns <- c(pattern1,pattern2) >strings <- c('TX.WT.CUT.mean','mg.tx.cv') > >Say I want to extract "WT.CUT" from the first string and "tx" from the >second string. If I do > >sub(patterns, '\\2', strings), only the first pattern will be used. > >looping the patterns doesn't work the way I want. Appreciate any >comments. >Thanks. > >Jun > > [[alternative HTML version deleted]] > >______________________________________________ >R-help at r-project.org mailing list -- To UNSUBSCRIBE and more, see >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.
Bert Gunter
2016-Sep-05 05:41 UTC
[R] element wise pattern recognition and string substitution
Well, he did provide an example, and...> z <- c('TX.WT.CUT.mean','mg.tx.cv')> sub("^.+?\\.(.+)\\.[^.]+$","\\1",z)[1] "WT.CUT" "tx" ## seems to do what was requested. Jeff would have to amplify on his initial statement however: do you mean that separate patterns can always be combined via "|" ? Or something deeper? Cheers, Bert Bert Gunter "The trouble with having an open mind is that people keep coming along and sticking things into it." -- Opus (aka Berkeley Breathed in his "Bloom County" comic strip ) On Sun, Sep 4, 2016 at 9:30 PM, Jeff Newmiller <jdnewmil at dcn.davis.ca.us> wrote:> Your opening assertion is false. > > Provide a reproducible example and someone will demonstrate. > -- > Sent from my phone. Please excuse my brevity. > > On September 4, 2016 9:06:59 PM PDT, Jun Shen <jun.shen.ut at gmail.com> wrote: >>Dear list, >> >>I have a vector of strings that cannot be described by one pattern. So >>let's say I construct a vector of patterns in the same length as the >>vector >>of strings, can I do the element wise pattern recognition and string >>substitution. >> >>For example, >> >>pattern1 <- "([^.]*)\\.([^.]*\\.[^.]*)\\.(.*)" >>pattern2 <- "([^.]*)\\.([^.]*)\\.(.*)" >> >>patterns <- c(pattern1,pattern2) >>strings <- c('TX.WT.CUT.mean','mg.tx.cv') >> >>Say I want to extract "WT.CUT" from the first string and "tx" from the >>second string. If I do >> >>sub(patterns, '\\2', strings), only the first pattern will be used. >> >>looping the patterns doesn't work the way I want. Appreciate any >>comments. >>Thanks. >> >>Jun >> >> [[alternative HTML version deleted]] >> >>______________________________________________ >>R-help at r-project.org mailing list -- To UNSUBSCRIBE and more, see >>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 -- To UNSUBSCRIBE and more, see > 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.