Need guidance in dealing with TCL regexp

Question

I need to process a random string which has the character ".." in-between. Like the one shown below

a..b/c..de/f-g..xyz..abc..def..123..

How can I get the data between these ".." using regexp?( this string can be of any length and I need to get each intermediate data set for further processing). Please guide me with this.

Thanks!

So you want `a`, `b/c`, `de/f-g`, `xyz`, `abc`, `def` and `123`? — Martin Ender, Oct 24 '12 at 19:26

score 6 · Accepted Answer · edited Oct 24 '12 at 19:57

6

If there is p.e. no newline in the string you could get a list of your strings with:

set in a..b/c..de/f-g..xyz..abc..def..123..
set out [split [string map {.. \n} $in] \n]]

edited Oct 24 '12 at 19:57

Andrew Cheong

29,362
15
90
145

answered Oct 24 '12 at 19:30

rene

76
1

A good character to map-to/split-on is `\ufffc` (the “object replacement character”) since you're really unlikely to encounter one of those in any real text. – Donal Fellows Oct 25 '12 at 08:31

score 1 · Answer 2 · answered Oct 25 '12 at 08:37

One tool to consider for this sort of thing, especially if the splitting term is more complex than the one in the question, is the textutil::split package in Tcllib. That lets you split strings by regular expression, like this:

package require textutil::split

set sample "a..b/c..de/f-g..xyz..abc..def..123.."
set RE {\.\.};  # “.” is an RE metacharacter, and so needs to be escaped
set pieces [textutil::split::splitx $sample $RE]

The above will also produce an empty element at the end of the pieces list, because there's a terminating separator.

The regular expression could also be `\.{2}`, but that's hardly simpler, or it could be `***=..` (a leading `***=` is a special Tcl RE engine feature for “just match the rest as a literal”). — Donal Fellows, Oct 25 '12 at 08:42

score 0 · Answer 3 · answered Oct 24 '12 at 20:01

0

You could use this regex:

[^..]

That would match all characters that are not ...

answered Oct 24 '12 at 20:01

Nick

4,302
2
24
38

I think this command would probably look at the beginning of the string for ".." and leaves the rest. I tried this and its not producing the required result. – Nathan Pk Oct 24 '12 at 23:45
@Nathan: Actually, that would be a command called `^..`. Or — more relevantly — a regular expression that matches anything except a `.` (because brackets enclose a character _set_). – Donal Fellows Oct 25 '12 at 08:39
@NathanPk When I tested this on `http://regexhero.net/tester/` it grabbed everything that wasn't `..` – Nick Oct 25 '12 at 15:02

Need guidance in dealing with TCL regexp

3 Answers3