Hi everybody,
I am currently struggling with javascript and regular expressions.
My purpose is to count "M" letters not preceded by F in a target string (see below).
The regex pattern "[^F]M" I thought to use doesn't work (even though I have successfully tried it in a freeware that checks regular expressions against test strings); I had to change it to "\.M|M\."
I have also encountered problems using "^" and "$" as start and end locators (not in this specific example).
Am I doing something wrong with the javascript or does the adobe regular expression engine have specific limitations I am not aware of?
Thank you for your help and please forget my terrible English.
Pierpaolo
-------------- target string
FC.FY
FM.CF.m
M.FV.FT
Fr.FV.FY
m.C.F
FC'.M
CF.FM
m.CF
FM.C
--------------javascript code NOT working
var tot=0;
var s = this.getField("Blends").value;
var match = /[^F]M/.test(s);
if (match) {
tot = (s.match("[^F]M","g")).length;
}
event.value = tot;
-----------------------------------
java script and regular expressions
2010-12-20 04:04:14
My Product Information:
Acrobat Pro 9.0, Macintosh
Acrobat Pro 9.0, Macintosh
2010-12-20 04:39:59
#2
Dear try67,
thank you for your quick reply. your bit of code is really helpful.
Actually I did realize that the pattern "\.M|M\." select M but also instances of FM. My code to subtract those instances from the total (thus obtaining true Ms) is absolutely clumsier than yours.
Pierpaolo
thank you for your quick reply. your bit of code is really helpful.
Actually I did realize that the pattern "\.M|M\." select M but also instances of FM. My code to subtract those instances from the total (thus obtaining true Ms) is absolutely clumsier than yours.
Pierpaolo
2010-12-20 04:45:51
#3
The pattern you had, /[^F]M/g , works well in most cases. It doesn't work when you have an M at the begining of the string. I tried to write a pattern to treat that case as well, but then it occured to me that the subtraction method is easier. However, if someone is able to write such a pattern, I'd love to see how it's done.
2010-12-20 05:16:35
#4
The strange thing is that the software I use for checking patterns "sees" even the Ms at the beginning of lines with [^F]M. I have downloaded a new software which behaves differently, not recognizing Ms at the beginning of lines. Well, who knows...
Again thanks.
Again thanks.
Here you can find out more about it:
http://www.w3schools.com/js/js_obj_regexp.asp
http://www.w3schools.com/jsref/jsref_obj_regexp.asp
As to your question. I would do it in the following way:
patt1 = /FM/g;
patt2 = /M/g;
tot = s.match(patt2).length - s.match(patt1).length;
There might be a way to combine both expressions into one, but that should work as well.
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