Regex to find specific pattern in R

Question

I have a dataset like below:

 dput(d1)
structure(list(FNUM = structure(1L, .Label = "20140824-0227", class = "factor"), 
    DESCRIPTION = "From : J LTo : [email protected] : Bcc : Sent On : Mon Apr 13 08:59:18 S 2015Subject : RE:Re: Suspect illegally modified vehiclesBody : Our Ref: BS-CT-1408-0665Date : 2-Apr-2015Our Ref: 2015/Jan/3224Date : 2-Apr-2015Thank you very much! Please conduct a thorough check on the vehicle other than the exhaust system. Warm regards,J L--------------------------------------------On Mon, 4/13/15, [email protected] <[email protected]> wrote: Subject: RE:Re: Suspect illegally modified vehicles To: [email protected] Received: Monday, April 13, 2015, 8:56 AM  Our Ref: GCE/VS/VS/VE/F20.000.000/38104 Date : 8-Apr-2015 Tel : 1800 2255 582 Fax : 6553 5329  -------------------------------------------- On Mon, 4/6/15, [email protected] <[email protected]> wrote:   Subject: Suspect illegally modified vehicles  To: [email protected]  Received: Monday, April 6, 2015, 11:06 AM    Our Ref:  GCE/VS/VS/VE/F20.000.000/37661  Date : 2-Apr-2015  Tel : 1812 2235 582  Fax : 6553 5329        Dear Ms L     Our records show that the vehicle bearing registration"), .Names = c("FNUM", 
"DESCRIPTION"), row.names = "1", class = "data.frame")

I use the below regex to identfiy values Our Ref:

> gsub(" *(Our Ref|Date) *:? *","",regmatches(d1[1,2],gregexpr("Our Ref *:[^:]+",d1[1,2]))[[1]])

[1] "BS-CT-1408-0665"                "2015/Jan/3224"                 
[3] "GCE/VS/VS/VE/F20.000.000/38104" "GCE/VS/VS/VE/F20.000.000/37661"

But i only wanted values of Our Ref: which starts with GCE , how do i limit my output to those values which begins with GCE.

Desired Result:

[1] "GCE/VS/VS/VE/F20.000.000/38104" "GCE/VS/VS/VE/F20.000.000/37661"

Updated For Second part of the problem:

dput(d1)
structure(list(FNUM = structure(1L, .Label = "20140824-0227", class = "factor"), 
    DESCRIPTION = "From : J LTo : [email protected] : Bcc : Sent On : Mon Apr 13 08:59:18 S 2015Subject : RE:Re: Suspect illegally modified vehiclesBody : Our Ref: BS-CT-1408-0665Date : 2-Apr-2015Our Ref: 2015/Jan/3224Date : 2-Apr-2015Thank you very much! Please conduct a thorough check on the vehicle other than the exhaust system. Warm regards,J L--------------------------------------------On Mon, 4/13/15, [email protected] <[email protected]> wrote: Subject: RE:Re: Suspect illegally modified vehicles To: [email protected] Received: Monday, April 13, 2015, 8:56 AM  Our Ref: GCE/VS/VS/VE/F20.000.000/38104 Date : 8-Apr-2015 Tel : 1800 2255 582 Fax : 6553 5329  -------------------------------------------- On Mon, 4/6/15, [email protected] <[email protected]> wrote:   Subject: Suspect illegally modified vehicles  To: [email protected]  Received: Monday, April 6, 2015, 11:06 AM    Our Ref:  GCE/QSMO/SQSS/SQ/F20.000.000/503533/lc  Date : 2-Apr-2015  Tel : 1812 2235 582  Fax : 6553 5329     Our Ref:  GCE/CC/PCF/FB/F20.000.000/233546/SK/PW  Date : 2-Apr-2015     Dear Ms L     Our records show that the vehicle bearing registration  "), .Names = c("FNUM", 
"DESCRIPTION"), row.names = "1", class = "data.frame")

> gsub(" *(Our Ref|Date) *:? *","",regmatches(d1[1,2],gregexpr("Our Ref *:\\s+GCE[^:]+",d1[1,2]))[[1]])
[1] "GCE/VS/VS/VE/F20.000.000/38104"         "GCE/QSMO/SQSS/SQ/F20.000.000/503533/lc"
[3] "GCE/CC/PCF/FB/F20.000.000/233546/SK/PW"

However i want to limit my result to

[1] "GCE/VS/VS/VE/F20.000.000/38104"         "GCE/QSMO/SQSS/SQ/F20.000.000/503533"
[3] "GCE/CC/PCF/FB/F20.000.000/233546"

which is i wanted only v1/v2/v3/v4/v5/v6 anything after 6 values should be removed or ends with number after 5 /(slashes).GCE/QSMO/SQSS/SQ/F20.000.000/503533/lc should change to GCE/QSMO/SQSS/SQ/F20.000.000/503533 and GCE/CC/PCF/FB/F20.000.000/233546/SK/PW should change to GCE/CC/PCF/FB/F20.000.000/233546

Rorschach · Accepted Answer · 2015-06-18 04:22:08Z

2

You can add in a requirement that "GCE" (with space before it) occurs before your [^:]

regmatches(d1[1,2],gregexpr("Our Ref *:\\s+GCE[^:]+",d1[1,2]))

EDIT: try this, you can match groups n numbers of times with {n},

gsub(" *(Our Ref|Date) *:? *", "",
     regmatches(d1[1,2], 
                gregexpr("Our Ref *:\\s+GCE(/[^/-]+){5}", 
                         d1[1,2], perl=T))[[1]])

edited Jun 18, 2015 at 4:22

answered Jun 18, 2015 at 3:35

Rorschach

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harihara sudan. s Over a year ago

@Legalizelt I have updated my question from your suggestion.(second problem). Thanks your first suggestion works!

Jota · Accepted Answer · 2015-06-18 05:10:32Z

1

Here is a different approach using strpslit to split on any non-digit character one or more times: \\D+ followed by a space:

splts <- strsplit(d1$DESCRIPTION, "\\D+ ")[[1]]
splts[grep("GCE", splts)]
# [1] "GCE/VS/VS/VE/F20.000.000/38104"      "GCE/QSMO/SQSS/SQ/F20.000.000/503533"
# [3] "GCE/CC/PCF/FB/F20.000.000/233546"

edited Jun 18, 2015 at 5:10

answered Jun 18, 2015 at 4:31

Jota

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