String Replacement

glerma

I am having some difficulty. I am fairly new to PHP Programming. I am looking for some input on how to do the following.

I want to be able to do some string replacements on specific strings. I have a form field that Im trying to populate , which has a long string derived from an Oracle CLOB column.
Here is what command-syntax that I'm using:
$fldIGPMESSAGEDATA = str_replace("ATN", "ACCOUNT TELEPHONE NUMBER", $fldIGPMESSAGEDATA);

This is the result:
ACCOUNT TELEPHONE NUMBER = "8504766372"

Here is another section in the string named "MATN", which has a different meaning of MAIN/ALTERNATE TELEPHONE NUMBER.

This section gets chaged as well as the "ATN" section.

The problem is that othes sections in the string may have ATN in it, causing them to be replaced as well.

How do I do patter-matching for the specific string "ATN" and nothing else, so that only it gets converted?

[deleted]

use preg_replace. Then you can define not only what should be replaced, but also what should come before or after the things that should be replaced.

http://www.php.net/manual/en/function.preg-replace.php

http://www.php.net/manual/en/pcre.pattern.syntax.php

glerma

I hate do bother you with this, but would you have a syntax example on how to replace the exact string of "ATN" to "ACCOUNT TELEPHONE NUMBER"?

I would give me a good start. I'm not good with regular expressions.

Thanks.

Anon

I don't if this is what your after...

$fldIGPMESSAGEDATA = "blah blah blah ATN blah blah blah";
$fldIGPMESSAGEDATA = preg_replace("|ATN|i", "ACCOUNT TELEPHONE NUMBER", $fldIGPMESSAGEDATA);
print $fldIGPMESSAGEDATA;

Mark
www.hdwt.com

[deleted]

Allmost.
The problem was that sometimes there was MATN in the string too, and that should not be replaced (reading the entire thread usually helps 🙂 )

Ok, hold on to your pants, here we go...

If you just want to replace any occurence of ATN, then just give a pattern that contains
exactly what you want to replace:
(the pattern must be delimited by two identical characters, it is customary to use slashes, but if you want the pattern itself to match
on slashes, you can use any other character)

$fldIGPMESSAGEDATA = "bla ATN MATN bla blah blah";
echo preg_replace("/ATN/", "ACCOUNT TELEPHONE NUMBER", $fldIGPMESSAGEDATA);

If you want to make the match case-insensitive, you can add an i after the pattern:

echo preg_replace("/ATN/i", "ACCOUNT TELEPHONE NUMBER", $fldIGPMESSAGEDATA);

Now, you want to match only ATN, not MATN, so you have to know that there is not an M in front of ATN.
You can make the pattern match on a set of characters by putting those characters in brackets: [agt] will match 'a' or 'g' or 't'.
You can make it match on 'anything BUT' those characters by adding a ^ sign: [^agt] will match on anything BUT 'a', 'g' or 't'.

So to match on ATN preceded by NOT an M:

echo preg_replace("/[^M]ATN/", "ACCOUNT TELEPHONE NUMBER", $fldIGPMESSAGEDATA);

But now you'll find that it replaces ATN, plus the character in front of it (which was not an M) That is because the 'NOT an M' characeter is part of the pattern that get's replaced.

You need to put that characters back in by using back-referencing.
In regexps you can define a block in the pattern by putting parentheses around it.
You can backreference to those blocks in the pattern itself and in the replacing string, by putting '\1' in to reference the first block, '\2' for the second etc.
In this case, I put parentheses around the 'NOT M' part, and I reference that block again at the start of the replacement string.
Now when the expression matches, it will replace '\1' with whatever it found in front of ANT that was not an M.

echo preg_replace("/([^M])ATN/", "\1ACCOUNT TELEPHONE NUMBER", $fldIGPMESSAGEDATA);

glerma

Wow, thanks to all. This is more than enough info for me to use. I really appreciate the detailed explanation.

I am now able to accomplish what I need.

Anon

An easier way is to use a word boundary

$regex = "/\bATN\b/i";

Mark
www.hdwt.com

[deleted]

lol that's true, I got so caught up in the NOT M thing that I forgot about that :-)

glerma

Well, I ended up using: $fldIGPMESSAGEDATA = preg_replace ("/([^{A-Z])CC([^A-Z])/",} "\1COMPANY CODE ", $fldIGPMESSAGEDATA);

I used A-Z to say "Not any character A-Z".

This seems to work pretty well, although, I'm conduction extensive testing on it. I did run into a couple of situations where the previous expression would look for "Not M", but would find characters after, such as the above example. CC would also replace CCNA, which would make CCNA look like COMPANY CODENA.

I will try using the word boundry to see if it parses out quicker.