| Re: Regarding split text and match from data base [message #183950 is a reply to message #183945] |
Thu, 28 November 2013 18:51   |
Ben Bacarisse
Messages: 82
Registered: November 2013
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Jerry Stuckle <jstucklex(at)attglobal(dot)net> writes:
> On 11/28/2013 7:27 AM, Ben Bacarisse wrote:
>> Jerry Stuckle <jstucklex(at)attglobal(dot)net> writes:
>> <snip>
>>> Here is a better version. It uses a regex to get all of the ip and
>>> mac addresses in an array, then selects them. I set this up for CLI
>>> output (for basic testing here), so you'll have to change the display.
>>> But otherwise it should work with few modifications and correcting for
>>> the line wrapping as indicated
>>>
>>> <?php
>>>
>>> $arp = shell_exec('arp -a');
>>>
>>> ----
>>>
>>> // *1
>>> $res=preg_match_all('/^\s*([0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3})\ s+([0-9a-fA-F]{2}\-[0-9a-fA-F]{2}\-[0-9a-fA-F]{2}\-[0-9a-fA-F]{2}\-[0-9a-fA -F]{2}\-[0-9a-fA-F]{2})/m',
>>> $arp, $matches, PREG_SET_ORDER);
>>
>> I'd do this a little differently. I'd use PREG_PATTERN_ORDER so that I
>> can just loop through $matches[2] without any further subscripting, but
>> I'd also not capture the IP address since it does not seem to be used.
>>
>
> The OP indicated he wanted to capture the IP address. We don't know
> what else he may be using it for. And I used PREG_SET_ORDER
> specifically to keep the IP address with the MAC address.
Without more code it's hard to tell, but for what I was commenting on,
pattern order looks better. The only advantage of either order is if
there is some natural operation that can be performed on $matches[i] and
there is no evidence for that as yet for 'set' order. There is a
natural operation that is done on all the macs, which it why, on the
balance of the current evidence, I'd favour pattern order.
<snip>
>> As a result of changing the capture order, I'd also be tempted to
>> re-write the loop:
>>
>> <snip>
>>> $macs = ''; // *4
>>> foreach ($matches as $match) {
>>> if ($macs != '') // Not the first time through, so
>>> $macs .= ', '; // Add a separator
>>> $macs .= '\'' . mysqli_real_escape_string($link, $match[2])
>>> . '\''; // Append the next MAC address (again all one line above)
>>> }
>>
>> as $macs = "'" . join("', '", $matches[1]) . "'";
>
> Which doesn't work when you capture both MAC and IP.
You can if you just write 2 instead of 1, but I suspect that's not what
you meant. You can't do this if you collect in 'set' order rather than
'pattern' order, but even if the IP address is captured there's no clear
reason to choose set order (so far as we know).
> Additionally,
> you don't call mysqli_real_escape_string() for the values. Yes, I
> know it's not actually required here - but it's a good habit for new
> programmers to get into. It's much better to call it when not needed
> than to not call it when it is needed.
Well, you can't mean that literally (there are places where it's not
needed where using it would break the code) but I know what you are
getting at. Part of the equation should be, in my view, how likely it
is that the quoting will be needed. Given the context (mac addresses)
it's not very likely, and I'd take that into account.
<snip>
--
Ben.
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