On Nov 13, 2009, at 8:12 AM, Dennis Fisher wrote:
Colleagues,
I am using R (2.9.2, all platforms) to search for a complicated text
string using regular expressions. I would appreciate any help you
can provide.
The string consists of the following elements:
SOMEWORDWITHNOSPACES
any number of spaces and/or tabs
(
any number of spaces and/or tabs
integer
any number of spaces and/or tabs
)
Examples include:
WORD ( 123 )
WORD(1 )
WORD\t ( 21\t)
WORD \t ( 1 \t )
etc.
I don't need to substitute anything, only to identify if such a
string exists.
Any help with regular expressions would be appreciated.
Thanks.
Dennis
How about this:
Lines <- c("WORD ( 123 )","WORD(1)", "WORD\t ( 21\t) ", "WORD\t
( 21\t) " )
> Lines
[1] "WORD ( 123 )" "WORD(1)" "WORD\t ( 21\t) "
[4] "WORD\t ( 21\t) "
> grep("^[A-Za-z]+.*\\(.*[0-9]+.*\\)", Lines)
[1] 1 2 3 4
You should test it on some real data to see if it works or needs to be
tweaked further.
^[A-Za-z]+ finds one or more characters at the beginning of the line
.* finds zero or more characters after the word
\\( finds an open paren
.* finds zero or more characters after the open paren
[0-9]+ finds one or more digits
.* finds zero or more characters after the digits
\\) finds the close paren
HTH,
Marc Schwartz
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