R help - Sep 2016 - element wise pattern recognition and string substitution

If you want to mach each element of 'strings' to a different regex, do
it. Here are three ways, using your original example.

pattern1 <- "([^.]*)\\.([^.]*\\.[^.]*)\\.(.*)"
pattern2 <- "([^.]*)\\.([^.]*)\\.(.*)"

patterns <- c(pattern1,pattern2)
strings <- c('TX.WT.CUT.mean','mg.tx.cv')

for(i in seq(strings)) print(sub(patterns[i], "\\2", strings[i]))

mapply(sub, pattern = patterns, x = strings, MoreArgs=list(replacement =
"\\2"))

library(stringi)
stri_replace_all_regex(strings, patterns, "$2")

Best,
Ista
On Tue, Sep 6, 2016 at 9:20 PM, Jun Shen <jun.shen.ut at gmail.com>
wrote:
> Hi Jeff,
>
> Thanks for the reply. I tried your suggestion and it doesn't seem to
work
> and I tried a simple pattern as follows and it works as expected
>
> sub("(3\\.mg\\.kg)\\.(>50-70\\.kg)\\.(.*)", '\\1',
"3.mg.kg.>50-70.kg.P05")
> [1] "3.mg.kg"
>
> sub("(3\\.mg\\.kg)\\.(>50-70\\.kg)\\.(.*)", '\\2',
"3.mg.kg.>50-70.kg.P05")
> [1] ">50-70.kg"
>
> sub("(3\\.mg\\.kg)\\.(>50-70\\.kg)\\.(.*)", '\\3',
"3.mg.kg.>50-70.kg.P05")
> [1] "P05"
>
> My problem is the pattern has to be dynamically constructed on the input
> data of the function I am writing. It's actually not too difficult to
> assemble the final.pattern with some code like the following
>
> sort.var <- c('TX','WTCUT')
> combn.sort.var <- do.call(expand.grid, lapply(sort.var,
>
function(x)paste('(',gsub('\\.','\\\\.',unlist(unique(all.exposure[x]))),
> ')', sep='')))
> all.patterns <- do.call(paste, c(combn.sort.var, '(.*)',
sep='\\.'))
> final.pattern <- paste0(all.patterns, collapse='|')
>
> You cannot run the code directly since the data object
"all.exposure" is
> not provided here.
>
> Jun
>
>
>
> On Tue, Sep 6, 2016 at 8:18 PM, Jeff Newmiller <jdnewmil at
dcn.davis.ca.us>
> wrote:
>
>> I am not near my computer today, but each parenthesis gets its own
result
>> number, so you should put the parenthesis around the whole pattern of
>> alternatives instead of having many parentheses.
>>
>> I recommend thinking in terms of what common information you expect to
>> find in these various strings, and place your parentheses to capture
that
>> information. There is no other reason to put parentheses in the
pattern...
>> they are not grouping symbols.
>> --
>> Sent from my phone. Please excuse my brevity.
>>
>> On September 6, 2016 5:01:04 PM PDT, Bert Gunter <bgunter.4567 at
gmail.com>
>> wrote:
>> >Jun:
>> >
>> >1. Tell us your desired result from your test vector and maybe
someone
>> >will help.
>> >
>> >2. As we played this game once already (you couldn't do it; I
showed
>> >you how), this seems to be a function of your limitations with
regular
>> >expressions. I'm probably not much better, but in any case, I
don't
>> >intend to be your consultant. See if you can find someone locally
to
>> >help you if you do not receive a satisfactory reply from the list.
>> >There are many people here who are pretty good at this sort of
thing,
>> >but I don't know if they'll reply. Regex's are
certainly complex. PERL
>> >people tend to be pretty good at them, I believe. There are
numerous
>> >web sites and books on them if you need to acquire expertise for
your
>> >work.
>> >
>> >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 Tue, Sep 6, 2016 at 3:59 PM, Jun Shen <jun.shen.ut at
gmail.com> wrote:
>> >> Hi Bert,
>> >>
>> >> I still couldn't make the multiple patterns to work. Here
is an
>> >example. I
>> >> make the pattern as follows
>> >>
>> >> final.pattern <-
>> >>
>> >"(240\\.m\\.g)\\.(>50-70\\.kg)\\.(.*)|(3\\.mg\\.kg)\\.(>
>> 50-70\\.kg)\\.(.*)|(240\\.m\\.g)\\.(>70-90\\.kg)\\.(.*)|(3\\
>> .mg\\.kg)\\.(>70-90\\.kg)\\.(.*)|(240\\.m\\.g)\\.(>90-110\\.
>> kg)\\.(.*)|(3\\.mg\\.kg)\\.(>90-110\\.kg)\\.(.*)|(240\\.m\\
>> .g)\\.(50\\.kg\\.or\\.less)\\.(.*)|(3\\.mg\\.kg)\\.(50\\.kg\
>> \.or\\.less)\\.(.*)|(240\\.m\\.g)\\.(>110\\.kg)\\.(.*)|(3\\.
>> mg\\.kg)\\.(>110\\.kg)\\.(.*)"
>> >>
>> >> test.string <- c('240.m.g.>110.kg.geo.mean',
'3.mg.kg.>110.kg.P05',
>> >> '240.m.g.>50-70.kg.geo.mean')
>> >>
>> >> sub(final.pattern, '\\1', test.string)
>> >> sub(final.pattern, '\\2', test.string)
>> >> sub(final.pattern, '\\3', test.string)
>> >>
>> >> Only the third string has been correctly parsed, which matches
the
>> >first
>> >> pattern. It seems the rest of the patterns are not called.
>> >>
>> >> Jun
>> >>
>> >>
>> >> On Mon, Sep 5, 2016 at 10:21 PM, Bert Gunter <bgunter.4567
at gmail.com>
>> >wrote:
>> >>>
>> >>> Just noticed: My clumsy do.call() line in my previously
posted code
>> >>> below should be replaced with:
>> >>> pat <- paste(pat,collapse = "|")
>> >>>
>> >>>
>> >>> > pat <- c(pat1,pat2)
>> >>> > paste(pat,collapse="|")
>> >>> [1] "a+\\.*a+|b+\\.*b+"
>> >>>
>> >>> ************ replace this **************************
>> >>> > pat <- do.call(paste,c(as.list(pat),
sep="|"))
>> >>> ********************************************
>> >>> >
sub(paste0("^[^b]*(",pat,").*$"),"\\1",z)
>> >>> [1] "a.a"   "bb"    "b.bbb"
>> >>>
>> >>>
>> >>> -- Bert
>> >>> Bert Gunter
>> >>>
>> >>> "The trouble with having an open mind is that people
keep coming
>> >along
>> >>> and sticking things into it."
>> >>> -- Opus (aka Berkeley Breathed in his "Bloom
County" comic strip )
>> >>>
>> >>>
>> >>> On Mon, Sep 5, 2016 at 12:11 PM, Bert Gunter
>> ><bgunter.4567 at gmail.com>
>> >>> wrote:
>> >>> > Jun:
>> >>> >
>> >>> > You need to provide a clear specification via regular
expressions
>> >of
>> >>> > the patterns you wish to match -- at least for me to
decipher it.
>> >>> > Others may be smarter than I, though...
>> >>> >
>> >>> > Jeff: Thanks. I have now convinced myself that it can
be done (a
>> >>> > "proof" of sorts): If pat1, pat2,..., patn
are m different
>> >patterns
>> >>> > (in a vector of patterns)  to be matched in a vector
of n strings,
>> >>> > where only one of the patterns will match in any
string,  then use
>> >>> > paste() (probably via do.call()) or otherwise to
paste them
>> >together
>> >>> > separated by "|" to form the concatenated
pattern, pat. Then
>> >>> >
>> >>> > sub(paste0("^.*(",pat,
").*$"),"\\1",thevector)
>> >>> >
>> >>> > should extract the matching pattern in each (perhaps
with a little
>> >>> > fiddling due to precedence rules); e.g.
>> >>> >
>> >>> >> z <-c(".fg.h.g.a.a",
"bb..dd.ef.tgf.", "foo...b.bbb.tgy")
>> >>> >
>> >>> >> pat1 <- "a+\\.*a+"
>> >>> >> pat2 <-"b+\\.*b+"
>> >>> >> pat <- c(pat1,pat2)
>> >>> >
>> >>> >> pat <- do.call(paste,c(as.list(pat),
sep="|"))
>> >>> >> pat
>> >>> > [1] "a+\\.*a+|b+\\.*b+"
>> >>> >
>> >>> >>
sub(paste0("^[^b]*(",pat,").*$"), "\\1", z)
>> >>> > [1] "a.a"   "bb"   
"b.bbb"
>> >>> >
>> >>> > Cheers,
>> >>> > Bert
>> >>> >
>> >>> >
>> >>> > Bert Gunter
>> >>> >
>> >>> > "The trouble with having an open mind is that
people keep coming
>> >along
>> >>> > and sticking things into it."
>> >>> > -- Opus (aka Berkeley Breathed in his "Bloom
County" comic strip )
>> >>> >
>> >>> >
>> >>> > On Mon, Sep 5, 2016 at 9:56 AM, Jun Shen
<jun.shen.ut at gmail.com>
>> >wrote:
>> >>> >> Thanks for the reply, Bert.
>> >>> >>
>> >>> >> Your solution solves the example. I actually have
a more general
>> >>> >> situation
>> >>> >> where I have this dot concatenated string from
multiple
>> >variables. The
>> >>> >> problem is those variables may have values with
dots in there.
>> >The
>> >>> >> number of
>> >>> >> dots are not consistent for all values of a
variable. So I am
>> >thinking
>> >>> >> to
>> >>> >> define a vector of patterns for the vector of the
string and
>> >hopefully
>> >>> >> to
>> >>> >> find a way to use a pattern from the pattern
vector for each
>> >value of
>> >>> >> the
>> >>> >> string vector. The only way I can think of is
"for" loop, which
>> >can be
>> >>> >> slow.
>> >>> >> Also these are happening in a function I am
writing. Just wonder
>> >if
>> >>> >> there is
>> >>> >> another more efficient way. Thanks a lot.
>> >>> >>
>> >>> >> Jun
>> >>> >>
>> >>> >> On Mon, Sep 5, 2016 at 1:41 AM, Bert Gunter
>> ><bgunter.4567 at gmail.com>
>> >>> >> wrote:
>> >>> >>>
>> >>> >>> Well, he did provide an example, and...
>> >>> >>>
>> >>> >>>
>> >>> >>> > z <-
c('TX.WT.CUT.mean','mg.tx.cv')
>> >>> >>>
>> >>> >>> >
sub("^.+?\\.(.+)\\.[^.]+$","\\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.
>> >>> >>
>> >>> >>
>> >>
>> >>
>>
>>
>
>         [[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.

On Tue, Sep 6, 2016 at 11:59 PM, Jun Shen <jun.shen.ut at gmail.com>
wrote:
> Hi Ista,
>
> Thanks for the suggestion. I didn't know mapply can be used this way!
Let me
> take one more step. Instead of defining a pattern for each string, I would
> like to define a set of patterns from all the possible combination of the
> unique values of those variables. Then I need each string to find a pattern
> for itself.
Uh, humn, what?!? I have no idea what this means. Example?

--Ista

 I know this is getting a little stretching. Thanks for all
the
> suggestion/comments from everyone.
>
> Jun
>
> On Tue, Sep 6, 2016 at 9:44 PM, Ista Zahn <istazahn at gmail.com>
wrote:
>>
>> If you want to mach each element of 'strings' to a different
regex, do
>> it. Here are three ways, using your original example.
>>
>> pattern1 <- "([^.]*)\\.([^.]*\\.[^.]*)\\.(.*)"
>> pattern2 <- "([^.]*)\\.([^.]*)\\.(.*)"
>>
>> patterns <- c(pattern1,pattern2)
>> strings <- c('TX.WT.CUT.mean','mg.tx.cv')
>>
>> for(i in seq(strings)) print(sub(patterns[i], "\\2",
strings[i]))
>>
>> mapply(sub, pattern = patterns, x = strings, MoreArgs=list(replacement
>> "\\2"))
>>
>> library(stringi)
>> stri_replace_all_regex(strings, patterns, "$2")
>>
>> Best,
>> Ista
>> On Tue, Sep 6, 2016 at 9:20 PM, Jun Shen <jun.shen.ut at
gmail.com> wrote:
>> > Hi Jeff,
>> >
>> > Thanks for the reply. I tried your suggestion and it doesn't
seem to
>> > work
>> > and I tried a simple pattern as follows and it works as expected
>> >
>> > sub("(3\\.mg\\.kg)\\.(>50-70\\.kg)\\.(.*)",
'\\1',
>> > "3.mg.kg.>50-70.kg.P05")
>> > [1] "3.mg.kg"
>> >
>> > sub("(3\\.mg\\.kg)\\.(>50-70\\.kg)\\.(.*)",
'\\2',
>> > "3.mg.kg.>50-70.kg.P05")
>> > [1] ">50-70.kg"
>> >
>> > sub("(3\\.mg\\.kg)\\.(>50-70\\.kg)\\.(.*)",
'\\3',
>> > "3.mg.kg.>50-70.kg.P05")
>> > [1] "P05"
>> >
>> > My problem is the pattern has to be dynamically constructed on the
input
>> > data of the function I am writing. It's actually not too
difficult to
>> > assemble the final.pattern with some code like the following
>> >
>> > sort.var <- c('TX','WTCUT')
>> > combn.sort.var <- do.call(expand.grid, lapply(sort.var,
>> >
>> >
function(x)paste('(',gsub('\\.','\\\\.',unlist(unique(all.exposure[x]))),
>> > ')', sep='')))
>> > all.patterns <- do.call(paste, c(combn.sort.var,
'(.*)', sep='\\.'))
>> > final.pattern <- paste0(all.patterns, collapse='|')
>> >
>> > You cannot run the code directly since the data object
"all.exposure" is
>> > not provided here.
>> >
>> > Jun
>> >
>> >
>> >
>> > On Tue, Sep 6, 2016 at 8:18 PM, Jeff Newmiller
>> > <jdnewmil at dcn.davis.ca.us>
>> > wrote:
>> >
>> >> I am not near my computer today, but each parenthesis gets its
own
>> >> result
>> >> number, so you should put the parenthesis around the whole
pattern of
>> >> alternatives instead of having many parentheses.
>> >>
>> >> I recommend thinking in terms of what common information you
expect to
>> >> find in these various strings, and place your parentheses to
capture
>> >> that
>> >> information. There is no other reason to put parentheses in
the
>> >> pattern...
>> >> they are not grouping symbols.
>> >> --
>> >> Sent from my phone. Please excuse my brevity.
>> >>
>> >> On September 6, 2016 5:01:04 PM PDT, Bert Gunter
>> >> <bgunter.4567 at gmail.com>
>> >> wrote:
>> >> >Jun:
>> >> >
>> >> >1. Tell us your desired result from your test vector and
maybe someone
>> >> >will help.
>> >> >
>> >> >2. As we played this game once already (you couldn't
do it; I showed
>> >> >you how), this seems to be a function of your limitations
with regular
>> >> >expressions. I'm probably not much better, but in any
case, I don't
>> >> >intend to be your consultant. See if you can find someone
locally to
>> >> >help you if you do not receive a satisfactory reply from
the list.
>> >> >There are many people here who are pretty good at this
sort of thing,
>> >> >but I don't know if they'll reply. Regex's are
certainly complex. PERL
>> >> >people tend to be pretty good at them, I believe. There
are numerous
>> >> >web sites and books on them if you need to acquire
expertise for your
>> >> >work.
>> >> >
>> >> >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 Tue, Sep 6, 2016 at 3:59 PM, Jun Shen <jun.shen.ut
at gmail.com>
>> >> > wrote:
>> >> >> Hi Bert,
>> >> >>
>> >> >> I still couldn't make the multiple patterns to
work. Here is an
>> >> >example. I
>> >> >> make the pattern as follows
>> >> >>
>> >> >> final.pattern <-
>> >> >>
>> >>
>"(240\\.m\\.g)\\.(>50-70\\.kg)\\.(.*)|(3\\.mg\\.kg)\\.(>
>> >>
50-70\\.kg)\\.(.*)|(240\\.m\\.g)\\.(>70-90\\.kg)\\.(.*)|(3\\
>> >>
.mg\\.kg)\\.(>70-90\\.kg)\\.(.*)|(240\\.m\\.g)\\.(>90-110\\.
>> >> kg)\\.(.*)|(3\\.mg\\.kg)\\.(>90-110\\.kg)\\.(.*)|(240\\.m\\
>> >> .g)\\.(50\\.kg\\.or\\.less)\\.(.*)|(3\\.mg\\.kg)\\.(50\\.kg\
>> >>
\.or\\.less)\\.(.*)|(240\\.m\\.g)\\.(>110\\.kg)\\.(.*)|(3\\.
>> >> mg\\.kg)\\.(>110\\.kg)\\.(.*)"
>> >> >>
>> >> >> test.string <-
c('240.m.g.>110.kg.geo.mean', '3.mg.kg.>110.kg.P05',
>> >> >> '240.m.g.>50-70.kg.geo.mean')
>> >> >>
>> >> >> sub(final.pattern, '\\1', test.string)
>> >> >> sub(final.pattern, '\\2', test.string)
>> >> >> sub(final.pattern, '\\3', test.string)
>> >> >>
>> >> >> Only the third string has been correctly parsed,
which matches the
>> >> >first
>> >> >> pattern. It seems the rest of the patterns are not
called.
>> >> >>
>> >> >> Jun
>> >> >>
>> >> >>
>> >> >> On Mon, Sep 5, 2016 at 10:21 PM, Bert Gunter
>> >> >> <bgunter.4567 at gmail.com>
>> >> >wrote:
>> >> >>>
>> >> >>> Just noticed: My clumsy do.call() line in my
previously posted code
>> >> >>> below should be replaced with:
>> >> >>> pat <- paste(pat,collapse = "|")
>> >> >>>
>> >> >>>
>> >> >>> > pat <- c(pat1,pat2)
>> >> >>> > paste(pat,collapse="|")
>> >> >>> [1] "a+\\.*a+|b+\\.*b+"
>> >> >>>
>> >> >>> ************ replace this
**************************
>> >> >>> > pat <- do.call(paste,c(as.list(pat),
sep="|"))
>> >> >>> ********************************************
>> >> >>> >
sub(paste0("^[^b]*(",pat,").*$"),"\\1",z)
>> >> >>> [1] "a.a"   "bb"   
"b.bbb"
>> >> >>>
>> >> >>>
>> >> >>> -- 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 Mon, Sep 5, 2016 at 12:11 PM, Bert Gunter
>> >> ><bgunter.4567 at gmail.com>
>> >> >>> wrote:
>> >> >>> > Jun:
>> >> >>> >
>> >> >>> > You need to provide a clear specification
via regular expressions
>> >> >of
>> >> >>> > the patterns you wish to match -- at least
for me to decipher it.
>> >> >>> > Others may be smarter than I, though...
>> >> >>> >
>> >> >>> > Jeff: Thanks. I have now convinced myself
that it can be done (a
>> >> >>> > "proof" of sorts): If pat1,
pat2,..., patn are m different
>> >> >patterns
>> >> >>> > (in a vector of patterns)  to be matched in
a vector of n
>> >> >>> > strings,
>> >> >>> > where only one of the patterns will match in
any string,  then
>> >> >>> > use
>> >> >>> > paste() (probably via do.call()) or
otherwise to paste them
>> >> >together
>> >> >>> > separated by "|" to form the
concatenated pattern, pat. Then
>> >> >>> >
>> >> >>> > sub(paste0("^.*(",pat,
").*$"),"\\1",thevector)
>> >> >>> >
>> >> >>> > should extract the matching pattern in each
(perhaps with a
>> >> >>> > little
>> >> >>> > fiddling due to precedence rules); e.g.
>> >> >>> >
>> >> >>> >> z <-c(".fg.h.g.a.a",
"bb..dd.ef.tgf.", "foo...b.bbb.tgy")
>> >> >>> >
>> >> >>> >> pat1 <- "a+\\.*a+"
>> >> >>> >> pat2 <-"b+\\.*b+"
>> >> >>> >> pat <- c(pat1,pat2)
>> >> >>> >
>> >> >>> >> pat <- do.call(paste,c(as.list(pat),
sep="|"))
>> >> >>> >> pat
>> >> >>> > [1] "a+\\.*a+|b+\\.*b+"
>> >> >>> >
>> >> >>> >>
sub(paste0("^[^b]*(",pat,").*$"), "\\1", z)
>> >> >>> > [1] "a.a"   "bb"   
"b.bbb"
>> >> >>> >
>> >> >>> > 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 Mon, Sep 5, 2016 at 9:56 AM, Jun Shen
<jun.shen.ut at gmail.com>
>> >> >wrote:
>> >> >>> >> Thanks for the reply, Bert.
>> >> >>> >>
>> >> >>> >> Your solution solves the example. I
actually have a more general
>> >> >>> >> situation
>> >> >>> >> where I have this dot concatenated
string from multiple
>> >> >variables. The
>> >> >>> >> problem is those variables may have
values with dots in there.
>> >> >The
>> >> >>> >> number of
>> >> >>> >> dots are not consistent for all values
of a variable. So I am
>> >> >thinking
>> >> >>> >> to
>> >> >>> >> define a vector of patterns for the
vector of the string and
>> >> >hopefully
>> >> >>> >> to
>> >> >>> >> find a way to use a pattern from the
pattern vector for each
>> >> >value of
>> >> >>> >> the
>> >> >>> >> string vector. The only way I can think
of is "for" loop, which
>> >> >can be
>> >> >>> >> slow.
>> >> >>> >> Also these are happening in a function I
am writing. Just wonder
>> >> >if
>> >> >>> >> there is
>> >> >>> >> another more efficient way. Thanks a
lot.
>> >> >>> >>
>> >> >>> >> Jun
>> >> >>> >>
>> >> >>> >> On Mon, Sep 5, 2016 at 1:41 AM, Bert
Gunter
>> >> ><bgunter.4567 at gmail.com>
>> >> >>> >> wrote:
>> >> >>> >>>
>> >> >>> >>> 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.
>> >> >>> >>
>> >> >>> >>
>> >> >>
>> >> >>
>> >>
>> >>
>> >
>> >         [[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.
>
>