search for: metacharacters

I thought that I can use metacharacters such as \w to match word characters with one backslash. But for some reason, I need to include two backslashes. > grepl(pattern='\w', x="what") Error: '\w' is an unrecognized escape in character string starting "\w" > grepl(pattern='\\w', x=&quot...

...T)], "va", myvector) grep identifies the element of the vector that matches my query, but it won't substitute the value. I have been reading the help pages for regular expression, but still can't figure out the syntax to read parenthesis and forward slashes, which are considered metacharacters. As usual, thank you for your help, Judith

I am trying to read some file names from an specific directory and such names contains metacharacters. The file names is like V4.35_T01-400720.csv In total I have 14 files for which the value T01 goes up to T14. I need to read the files into a string vector that looks like >names"V4.35_T01-400720.csv" "V4.35_T02-400720.csv" ... "V4.35_T14-400720.csv" So far, I hav...

for the script, please kindly see the script below. At line 10 and line 13, my problems occurs. The first one is I try to retrieve the gene official name from a column of a table. The pattern of official name is something starting with gene_name. For detail problems, please see the according lines. Any suggestions are appreciated example of matching source (extract the Nnat, sometime it would

...h.csv" Warning messages: 1: '\.' is an unrecognized escape in a character string 2: unrecognized escape removed from "[\.]csv$" R reference for regular expressions says "Any metacharacter with special meaning may be quoted by preceding it with a backslash. [...] The metacharacters in EREs are . \ | ( ) [ { ^ $ * + ?" Am I missing something here? If "\." is not the right way to match a period, can anyone tell me what is? I can't find anything on this in R reference... I'm using R 2.6 on Windows XP Thanks, Alec Zwart CMIS CSIRO alec.zwart at csir...

On Fri, 2015-02-13 at 23:46 -0600, Les Mikesell wrote: > I think you are missing some very basic concepts here. First, the > shell likes to parse things separated by white space. Second, [ is a > synonym for test which is a build-in version of /bin/test, so try 'man > test' for the syntax of tests. And third, you generally should use > double quotes around variables in

...to match <0.5.5. > > Ah, sorry. dash 0.5.4 and earlier don't compile on my system, so they > are not included in my conveniently accessible arsenal of test shells. > > > As for my patches, that was by accident and doesn't work reliably. When > > the shell sees no metacharacters, pathname expansion is bypassed, and > > backslash isn't considered a metacharacter. Which got me to my original > > example of /de\v: there are no metacharacters in there, so the shell > > doesn't look to see if it matches anything. Which seems highly > > desirable:...

...to match <0.5.5. > > Ah, sorry. dash 0.5.4 and earlier don't compile on my system, so they > are not included in my conveniently accessible arsenal of test shells. > > > As for my patches, that was by accident and doesn't work reliably. When > > the shell sees no metacharacters, pathname expansion is bypassed, and > > backslash isn't considered a metacharacter. Which got me to my original > > example of /de\v: there are no metacharacters in there, so the shell > > doesn't look to see if it matches anything. Which seems highly > > desirable:...

...", "aaa". I can easily identify these strings with grep("^Ig", X), but if I use this criterion in the sub() function (sub("^Ig", "0", X) I obviously get "0A", "0G" etc. I didn't expect to do it in this way and I tried with metacharacters and regexps in order to grep and substitute the whole word (\b \>, $). I don't post here my tryings, because they were obviously wrong. Please can you help me? Giulio _________________________________________________________________ Carica e scarica in un clic. Fino a 25 G...

...s while specifying destination constraints, if the PKCS#11 token returned multiple keys then only the first key had the constraints applied. Use of regular private keys, FIDO tokens and unconstrained keys are unaffected. * ssh(1): if an invalid user or hostname that contained shell metacharacters was passed to ssh(1), and a ProxyCommand, LocalCommand directive or "match exec" predicate referenced the user or hostname via %u, %h or similar expansion token, then an attacker who could supply arbitrary user/hostnames to ssh(1) could potentially perform command injection de...

Hello, when I use list.files with recursive = TRUE and all.files = TRUE, R returns a list of strings/paths. >From all those strings I want to keep only the ones starting with a . I tried using grep to achieve that. However, the problem is that because of the recursive list.files parameter, for some files beginning with a . there is a path attached. I think it is not as simple as it looks

-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 On 14/02/15 16:53, Les Mikesell wrote: <snip> > To understand it completely you need to know the order of > operations as the shell makes multiple passes over the line, > parsing, processing metacharacters, and expanding variables. And > I don't know where to find a concise description of that any more. man bash, about 900 lines down under "EXPANSION". -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.22 (GNU/Linux) iQIcBAEBAgAGBQJU34eBAAoJEAF3yXsqtyBlNuYP/iPLOPY/SbXeGgpZOnJKZ3qH...

Hi there, I rejoiced when I realized that you can use Perl regex from within R. However, as the FAQ states "Some functions, particularly those involving regular expression matching, themselves use metacharacters, which may need to be escaped by the backslash mechanism. In those cases you may need a quadruple backslash to represent a single literal one. " I was wondering if that is really necessary for perl=TRUE? wouldn't it be possible to parse a string differently in a regex context, e.g. aut...

...s while specifying destination constraints, if the PKCS#11 token returned multiple keys then only the first key had the constraints applied. Use of regular private keys, FIDO tokens and unconstrained keys are unaffected. * ssh(1): if an invalid user or hostname that contained shell metacharacters was passed to ssh(1), and a ProxyCommand, LocalCommand directive or "match exec" predicate referenced the user or hostname via %u, %h or similar expansion token, then an attacker who could supply arbitrary user/hostnames to ssh(1) could potentially perform command injection de...

...hanks for that. I assumed if test 1 worked, so would test 2. > > Have re-run test 2 with > > >> 16 if [ $file = "law00css" ] You still missed the part about quoting variables. You quote plain strings to hold embedded spaces together (or single-quotes to avoid parsing metacharacters). You use double quotes around $variables so they don't disappear completely if the variable isn't set, causing a syntax error. To understand it completely you need to know the order of operations as the shell makes multiple passes over the line, parsing, processing metacharacters, and e...

Hello all, I have a simple question: I have filenames that look like these: "n031ku09.10msmeanc" "n031ku10.10msmeanc" "n031ku11.10msmeanc" [22] "n031ku12.10msmeanc" "n031ti01.10msmeanc" "n031ti02.10msmeanc" I also have a set of the same without the "c" at the end. When I run list.files(".",

Why sometimes one has to put a double backslash in regular expressions, but often simple backslashes work too? Is only a \ required for giving a metacharacter its usual meaning? --------------------------------------- u=grep('\\{[\\-u]x',a,perl=T) # equivalent to u=grep('\{[\-u]x',a,perl=T) # but u=grep('\w',a,perl=T) # is not correct and requires

I can't open a file (on our samba server) using Actis, When I troubleshoot the problem using Wireshark, see SMB protocol using FIND_FIRST2 and filename using obscure Windows metacharacters, e.g. USAARG03V>>A.SWK , which gives STATUS_NO_SUCH_FILE (Samba is interpreting the name literally) But if the files are copied to a local drive Actis can find them. Thanks for your help.

Hi, I have a string of text as follows "LOI ." How do I replace the dot with "(%)" gsub(".","(%)",LOI .) gives "(%)(%)(%)(%)(%)" Thanks -- Shane [[alternative HTML version deleted]]

Hi, I guess the backslash should not be used as the separator for strsplit() in compareVersion(), because the period in [.] is no longer a metacharacter (no need to "escape" it using a backslash): https://github.com/wch/r-source/blob/trunk/src/library/utils/R/packages.R#L866-L867 > compareVersion function (a, b) { .... a <- as.integer(strsplit(a, "[\\.-]")[[1L]])