Converting space- to tab-delimited
alex at tweedly.net
Mon Feb 28 14:51:26 CST 2005
James.Cass at sealedair.com wrote:
>Here is yet another version:
>put replaceText(tText, "\s+", tab) into tText
Now that you've had 3 versions (all of them correct), it might be worth
a quick explanation, so you don't go away thinking Regex is a "black art".
RegEx allows the "unix-style" (or C-style, or Perl-style) quoting of
special characters, so "\s" means "(space)" - so the two versions of
"\s+" and " +" are effectively the same - choose whichever you find
easier to read.
Normally in regex,
"*" (asterisk) means "0 or more of the preceding character (or
"+" (plus) means "1 or more of the preceding character (or expression)".
So, "ab+c" would match "abc" or "abbc" or "abbbc" or ..... etc.
and "ab*c" would match all of those, and would also match "ac" ("a"
followed by 0 "b"s followed by "c")
This means that " +" means "one or more spaces" while " *" would mean
"zero or more spaces" -
EXCEPT that there's a special case of not matching the empty string due
to the "*" (that may not be the technically correct way to describe
it, but it's the one that I can understand, and is close enough :-)
So in the special case where the *entire* regular expression is
qualified by a "*", it acts like "one or more" instead of "zero or more".
There - simple , eh ? :-) :-)
Seriously, there's a learning curve, but regexes are very powerful;
there are lots of tutorials and tools available out on the web (search
through Google - I don't have a favourite I'd recommend), including
Frederic Rinaldi's rev-based regexbuilder - see
Alex Tweedly http://www.tweedly.net
No virus found in this outgoing message.
Checked by AVG Anti-Virus.
Version: 7.0.300 / Virus Database: 266.5.1 - Release Date: 27/02/2005
More information about the use-livecode