parsing numeric values
A minor variant might be the following: library(gsubfn) strapply(input, "\\d+\\.\\d+E[-+]?\\d+", as.numeric, simplify = rbind) where: - as.numeric is used in place of c in which case we do not need combine - \\d+ matches one or more digits - \\. matches a decimal point - [-+]? matches -, + or nothing (i.e. an optional sign). - parentheses around the regular expression not needed
On Wed, Nov 18, 2009 at 7:28 AM, Henrique Dallazuanna <wwwhsd at gmail.com> wrote:
Try this: strapply(input, "([0-9]+\\.[0-9]+E-[0-9]+)", c, simplify = rbind, combine = as.numeric) On Wed, Nov 18, 2009 at 9:57 AM, baptiste auguie <baptiste.auguie at googlemail.com> wrote:
Dear list,
I'm seeking advice to extract some numeric values from a log file
created by an external program. Consider the following example,
input <-
readLines(textConnection(
"some text
?<ax> = ? ?1.3770E-03 ? ? <bx> = ? ?3.4644E-07
?<ay> = ? ?1.9412E-04 ? ? <by> = ? ?4.8840E-08
other text
?<aax> ?= ? ?1.3770E-03 ? ? <bbx> = ? ?3.4644E-07
?<aay> ?= ? ?1.9412E-04 ? ? <bby> = ? ?4.8840E-08"))
## this is what I want
results <- c(as.numeric(strsplit(grep("<ax>", input,val=T), " ")[[1]][8]),
? ? ? ? ? ? as.numeric(strsplit(grep("<ay>", input,val=T), " ")[[1]][8]),
? ? ? ? ? ? as.numeric(strsplit(grep("<aax>", input,val=T), " ")[[1]][9]),
? ? ? ? ? ? as.numeric(strsplit(grep("<aay>", input,val=T), " ")[[1]][9])
? ? ? ? ? ? )
## [1] 0.00137700 0.00019412 0.00137700 0.00019412
The use of strsplit is not ideal here as there is a different number
of space characters in the lines containing <ax> and <aax> for
instance (hence the indices 8 and 9 respectively).
I tried to use gsubfn for a cleaner construct,
strapply(input, "<ax> += +([0-9.]+)", c, simplify=rbind,combine=as.numeric)
but I can't seem to find the correct regular expression to deal with
the exponent.
Any tips are welcome!
Best regards,
baptiste
______________________________________________ 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.
-- Henrique Dallazuanna Curitiba-Paran?-Brasil 25? 25' 40" S 49? 16' 22" O
______________________________________________ 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.