When to, and when not to use quotations in PHP

[Highway of Life]

Lew, you are saying that if a script uses ' for strings, and it takes one second to parse... using " would take 100 seconds to parse... this is not the case.
The difference is actually only about 50%, or 2 times faster to use single quotes... not 100 times faster.

Here is a test I ran to show the difference...

Spoiler:

Code: Select all

<?php
function get_microtime($time)
{
       list ($usec, $sec) = explode(" ", $time);
       return ((float) $usec + (float) $sec);
}

$start = microtime();
$array = array();
for ($i = 0; $i < 100; $i++)
{
    array_push($array, "Star Trek Guide");
}

$end = microtime();
$double_quote = (get_microtime($end) - get_microtime($start));
print "<pre>double quotes: $double_quote<br>";

unset($array);

$start = microtime();
$b_array = array();
for ($i = 0; $i < 100; $i++)
{
     array_push($b_array, 'Star Trek Guide');
}
$end = microtime();
$single_quote = (get_microtime($end) - get_microtime($start));
$result = $double_quote - $single_quote;
print "single quotes: $single_quote<br />difference...: $result</pre>";
?>

Result:

Code: Select all

double quotes: 0.000489950180054
single quotes: 0.000220060348511
difference...: 0.000269889831543

The difference is negligible, but if you use " a lot in your code, you might start to notice a difference.
Again, it's still better to use ', but you can use " when you need to... I still don't think it's good practice to use a lot of \'... unless you have a lot of them... and in that case, you should escape the quotes.
phpBB3 actually uses double quotes on almost every SQL query.

[Michaelo]

Next day bump!

LEW21, if you use the ? in language file with phpBB3 it will produce a ? not a ?. This is, I assume, a phpBB problem ( Unicode UTF-8 decoding of an Apostrophe ), I note both IE and Firefox show the '?'... but if you change IE to autoselect encoding it selects UTF-8 and displays correctly as too does FF when you select 8859-1... IE may add additional decoding for UTF8 to support several additional characters including the apostrophe...

I note, here it works... I bet its \' in the language file and not ?

And to think I have an apostrophe in my name... this is incorrect O'Toole and this is correct O?Toole. Now, what's the difference between ' and ? ?

[A_Jelly_Doughnut]

One thing to keep in mind: many (my self included) consider it bad form to do this:

Code: Select all

$foo = "moo {$bar['asdf']};

I prefer to do concatenation.

Code: Select all

$foo = 'moo' . $bar['asdf'];

Single quote (') is an ASCII character. Apostrophe is not. That's the short form of it.

[Michaelo]

Some info: http://www.fileformat.info/info/unicode ... /index.htm

It appears that there are three different single quotes...
See Also apostrophe U+0027
modifier letter apostrophe U+02BC
heavy single comma quotation mark ornament U+275C
I started off confused and now I am more confused than ever...

[Handyman]

I started off confused and now I am more confused than ever...

I'm happy we could help
Go with the first post Highway had in this topic
It makes it all very clear and running the time script Highway had, sometimes double quotes come out faster than single quotes? just depends on the day so the time difference of using them is negligible

I took Highways script and made it loop 1000 times and added up all the numbers and sometimes single is faster, other times double is faster? however, double is faster most of the time.
Here is the last time I refreshed the page

Single = 0.394691944122 ... Double = 0.2978079319 ... Result = 0.0968840122223

in that case, after going through it 1,000 times, double is faster by almost 1/100th of a second? not much either way.
The worst I have seen it for double is slower by almost 2/10ths of a second
and for single is almost 4/10ths of a second.

Spoiler:

Code: Select all


<?php
    function get_microtime($time)
    {
           list ($usec, $sec) = explode(" ", $time);
           return ((float) $usec + (float) $sec);
    }
function test_quotes()
{
    $row = array();
    $start = microtime();
    $array = array();
    for ($i = 0; $i < 100; $i++)
    {
        array_push($array, "Star Trek Guide");
    }
    
    $end = microtime();
    $double_quote = (get_microtime($end) - get_microtime($start));
    print "<pre>double quotes: $double_quote<br>";
    
    unset($array);
    
    $start = microtime();
    $b_array = array();
    for ($i = 0; $i < 100; $i++)
    {
         array_push($b_array, 'Star Trek Guide');
    }
    $end = microtime();
    $single_quote = (get_microtime($end) - get_microtime($start));
    $result = $double_quote - $single_quote;
    print "single quotes: $single_quote<br />difference...: $result</pre>";
    $row = array(
        'double'    => $double_quote,
        'single'    => $single_quote,
        'result'    => $result,
    );
    return $row;
    unset($row);
}
$single = $double = $result = 0;
for ($i = 0; $i < 1000; $i++)
{
    $row = test_quotes();
    $single += $row['single'];
    $double += $row['double'];
}
$result = $single - $double;
echo 'This is it<br />';
echo "Single - $single ... Double - $double ... Result - $result";
?>

One thing to keep in mind: many (my self included) consider it bad form to do this:

Code: Select all

$foo = "moo {$bar['asdf']};

phpBB uses that a lot in the new phpBB3.
Here is a bit of code from posting.php

Code: Select all


$sql = 'UPDATE ' . POSTS_TABLE . "
SET post_time = $current_time
WHERE post_id = {$post_data['topic_last_post_id']}
AND topic_id = $topic_id";
$db->sql_query($sql);


As Highway pointed out, they use double quotes on almost every sql query, and using

Code: Select all

"{$foo['bar']}";

is not bad coding? it just saves space and looks cleaner.
And you don't have to keep breaking out of quotes to get it done.

[Highway of Life]

I should add, that using ? is actually desired over ' in the language files, since the language files are saved as UTF-8.
For note, StarTrekGuide language files are using 85 ? (that key is getting easier to hit all the time. ) apostrophes in 71 language files.
If your text editor does not support UTF-8 OR saves files as Western by default, it will cause a problem with the language files, so be sure to save those files as UTF-8.

For more info, please see the olympus wiki Coding Guidelines (in progress )
I have not added the section that deals with quotations, but a full explanation will be in there when I get to that part.
At that time, I'll spell it out in complete detail for everyone.

[Michaelo]

There are two issues re apostrophe?s...
The first is the way your editor saves files and the second is the way your browser view pages...

Easy to fix... we should all use UTF-8 from now on (but I still don't have a key for apostrophe )
Mike

[Highway of Life]

There must be a way!

Check here, this will help you a little... http://www.fileformat.info/tip/microsof ... nicode.htm

Do you have any key combinations for things like these?

Code: Select all

Option...
`¡?£¢?§¶?ªº??«???ø?¨¥?®´??åß??©???¬?æ÷??µ???ç??

Option + Shift...
`???????°·??±»???Ø?¨Á??´??ÅÍÎÏ?ÓÔ?ÒÚÆ¿?¯Â???Ç?¸

[Michaelo]

No options Key... I can produce all ascii using Alt (num Lock on) and entering acsii code in numeric pad...
All other combinations including Alt, Ctrl, Shift (or combinations) and any key are fine but none produce the (real) apostrophe...

[Highway of Life]

Try using 'alt' with the numeric keypad.

'alt' 0145 = ?
'alt' 0146 = ?
'alt' 0147 = ?
'alt' 0148 = ?

All the codes are available from the 'character map' application.