please clarify this for me

[coiL]

Hi,
I feel stupid having to ask this - but if I don't have it explained I will never learn properly ..so .. Could someone please clarify a few things for me in very (very very) plain english. I know where to put them in the code but don't really understand specifically what they do.

($row = mysql_fetch_array($result) ) 

mysql_num_rows($query) 

also this which I don't really understand at all:

$_GET 

thanks.

[petesmc]

Hi,

The first example you gave, basically takes the result of your database query, and places them into the array called $row from your example. You would use a while loop to cycle through them.

The second example counts the number of rows that your query returned. So if you did "SELECT * FROM table" where your table have 1001 record, then if you did

//Sometime the $query part is left out
echo mysql_num_rows($query); 

It would print 1001.

In your last example, $_GET is a super global variable. It contains any information that a URL or form sent to the script by the GET method. You can also send by the POST method.

<?php
if(empty($_POST['fname'])) {
?>
<form method="POST" action="<?php echo $_SERVER['PHP_SELF']; ?>">
<input type="text" name="fname">
</form>
<?php
} else {
echo $_POST['fname'];
}

Say you had the form above and submitted the form. The value you put in the text box ('fname') will be sent to the script. That value will be stored in $_POST['fname'], where the text between the brackets is the name of the variable that was sent. If you sent via the GET method, it would be $_GET['fname'].

Just FYI, $_SERVER is another one of these special varialbes, and the value of $_SERVER['PHP_SELF'] is the name of the script that is currently running.

Hope this helped a little bit,
-Peter

[coiL]

thanks that helped me a bit

while I'm here , I was wondering what is the correct way to write an echo statement? I've seen it written in a few ways and was wondering which was correct?

echo("Hello world!");
echo "Hello World!"; 

[petesmc]

Hi,

You can do it any way really, though this is recommended:

echo 'My name is Peter'; 

Notice the single quotes instead of double. To print a variable you would do the following:

$var = 'Hello!';
echo $var; 

And to print both a string and a variable at the same time you would do this:

$var = 'Hello!';
echo $var . ' My Name is Peter!'; 

[coiL]

ok Thanks
I'll have to get used to doing it like that

is this right?

$username = $row["username"]; 

or should it be:

$username = $row['username']; 

[petesmc]

Hi,

Use the second one.

-Peter

[coiL]

ok thanks again

[mattjacob]

Originally posted by petesmc
And to print both a string and a variable at the same time you would do this:

$var = 'Hello!';
echo $var . ' My Name is Peter!'; 

But... that's what double quotes are for.

$var = 'Hello!';
echo "$var My Name is Peter!"; 

[petesmc]

You should remain consistent with how you print them out, if you are constantly switching between double and single it gets confusing. Also, then when you have to print a record of an array you end up doing:

echo "HI there {$name[0]}"; 

Instead of sticking to the same method which would be:

echo 'Hi there ' . $name[0]; 

Not to mention, single quotes are faster...

-Peter

[mattjacob]

Originally posted by petesmc
Not to mention, single quotes are faster...

In this case the difference would be negligible, but I do agree with you that the general rule is to use the least powerful quoting technique necessary.

However, you can't always use single-quoted strings. For example, the newline character can only be represented in a double-quoted string. And what if you wanted a multiline string? Then you'd need

$foo = <<< foo_bar
some pointless text
and another line
ooh, the third line
foo_bar; 

[petesmc]

That's the problem with the single quote method. But to get around that i just do this:

<?php
define("CR","\n");
echo 'Hi there!' . CR . 'My name is Peter!';
?>

Also, in function parameters, I've personally found double quotes to be faster for some reason. Of course I tested this by funny a function several time, but it took 10 million calls to a function to notice any difference in speed. Personally, i use double quotes for function parameters, and single for variables and echo.

-Peter

[samsm]

From close to the end of http://www.sitepointforums.com/showt...threadid=54074

Originally posted by MattR
I think the official word from Zend (et al) is that you should abandon the use of double-quotes since the process to find variables in the quotes is quite costly. Not to mention it craps out quite soon (you can run benchmarks and it will eventually kill PHP).

Can't say I have personally run tests to try that out but it is generally in sync with what I have read in the past.

[samsm]

Coil:
Although you seem to be getting this stuff pretty quickly, I recommend you check out...
http://www.zend.com/manual/language.types.string.php
and
http://www.zend.com/manual/language.types.array.php
and...
any other pages there you might find interesting

[mgkimsal]

Originally posted by samsm
I think the official word from Zend (et al) is that you should abandon the use of double-quotes since the process to find variables in the quotes is quite costly. Not to mention it craps out quite soon (you can run benchmarks and it will eventually kill PHP).

Funny, you'd think they'd want people to use " all the time so that there'd be more demand for the optimizer and encoder products.

[coiL]

Thanks everyone for the info and the links. I bought "Sam's Teach yourself PHP in 24 hours" today so hopefully I won't have to ask so many questions now