Another Reg Exp Quest

Anon

I dont seem to be getting these regular expressions. Sorry for all the questions. When i do a (.*) between two strings, i thought it would capture everything between those two strings for instance i have the following html code.

<TR VALIGN=TOP>
<TD ALIGN=RIGHT BGCOLOR="#FFFFFF"> Temperature </TD>

Im trying to get the 34.0 from it. So I tried this eregi

$Grab = eregi("Temperature </TD>

<TD> ([0-9].[0-9]) F", $ReadFile, $Display);

Which gave me nothing and i also tried this
$Grab = eregi("Temperature </TD>

<TD>(.*)", $ReadFile, $Display);

Which should by my understanding captured 34.0 F (1.1 C)

But i got nothiing. If you see what im doing wrong, any help would be greatly appreciated.

Thanks.

Ira

[deleted]

(.) matches everything
this includes the very string that you want to use as an end-marker.
And because the (.) already matches the end marker to, there is no end-marker left to match by the real end-marker. Am I still making sense?

if you have this regexp:
start(.*)end

and you have this string
start hello there end

then "start" would match "start",
and (.*) would match " hello there end"

and "end" can't match because there is nothing left to match on.

Instead of using (.*), use an expression that matches "everything but the end marker"

In the case of matching "</td>" as an end-marker,
you'd match the "middle" part with:
[^<]* (zero or more times "not a < sign")

Anon

Sorry but im still somewhat confused. What exactly does the [^<]* match and does it match the middle section or the end section. I know what the first section is gonna be and i know what the end section is gonna be. The middle is the dynamic part which i dont know what its going to be. And thats the number that i need.

Also i have another question, eregi stores its results in an array. For instance i used a variable called Display in eregi to store my results. Which element do i need to access to see if i got the correct result Display[0] or Display[1] in the examples i have seen using eregi i have seen both. Also What gets stored there would it be the first,middle, or last section of the string or the whole string. What i think im searching for is the middle section not the whole thing. Is that the case. Sorry if i sound all wacky, this is something new to me.

Thanks for all your help.

Ira

[deleted]

the [^<]* matches "zero or more occurences of "not <"
the brackets form a group around some characters, and the characters are a ^ for "not" and a < for <.
The star behind it means "zero or more times"

Using this means that everything will be matched, upto the first occurence of <. (the < itself is not matched)

And < is the start of your end marker, so it will match upto the end-marker, but not uncluding the end-marker.
The end-marker is matched by the ned-marker that you put into the reg-exp.

So if you put this as the pattern for the middle-part, it should work.

However, if you are just looking for a number you can also match on numbers:
[.0-9]+
This means:
match on a dot (escaped with a slash because the dot is also a regexp-operator, this tells PHP to use the dot as a dot, not as an operator) and the range of numbers from 0-9. The + means any of the characters in the brackets must occur at least once. (so empty strings are not allowed)

The simplest way to find out exactly what is stored in the array is to print the array using print_r($array) or var_dump($array)