neater code.. ternary & $argv

[Mad_T]

Hopefully simple questions...

Is there a better way to code this :

if (isset($argv[1) && $argv[1] == "name") echo "name =".$argv[1]."\r\n";

Specifically this part :
if (isset($argv[1) && $argv[1] == "name")

Is it possible to have multiple statements using ternary if returned true :

(isset($argv[1]) && $argv[1] == "name") ? $a=1; $b=2; $c=3 end : $a="NO";

Can you include 'code' in a ternary result ?

$var = (isset($argv[1])) ? 'mysql_connect SERVER A' : 'mysql_connect SERVER B';

( obviously I'd want to include full mysql connection details if possible )

I think the answer to both ternary questions is NO.. so what's easiest/neatest way ? a normal if else ??

Thanks 🙂

[Weedpacket]

Yes, as long as every statement is an expression (so that the values of all those expressions, when evaluated, can be combined into a single expression which is what each operand of the conditional operator needs to be); but a simple if/else construct would be tidier and less likely to be miswritten and therefore buggy.

Yes, depending on what "'code'" means - from the example it appears to mean "an expression", which is exactly what is supposed to go in the second and third operands of the conditional operator.

[Mad_T]

Sorry having a dumb moment !

Is there a neater way to write my first snippet of code ?

Yes, as long as every statement is an expression (so that the values of all those expressions, when evaluated, can be combined into a single expression which is what each operand of the conditional operator needs to be); but a simple if/else construct would be tidier and less likely to be miswritten and therefore buggy.

Normally I'd do a simple :

if ($var=="1) {
$a=1;
$b=5;
$c=7;
} else {
$a="No";
}

Could I write that as ternary ?

The "mysql_connect SERVER A" would be something like :
mysql_connect("localhost","mysql_user","mysql_pwd");

So can I do :

$var = (isset($argv[1])) ? 'mysql_connect("localhost","mysql_user","mysql_pwd");' : 'mysql_connect("remotehost","mysql_user","mysql_pwd");'; 

[traq]

Mad_T;11003927 wrote:

Is there a neater way to write my first snippet of code ?

yes, but mostly it involves simply fixing all your typos. Also, for single-line [font=monospace]if[/font] statements, I recommend always using {brackets}. It reduces the potential for bugs later on:

if ( isset($argv[1]) && $argv[1] === "name" ){ echo "name = {$argv[1]}\r\n";  }

Mad_T;11003927 wrote:

Normally I'd do a simple :

if ($var=="1) {
$a=1;
$b=5;
$c=7;
} else {
$a="No";
}

Could I write that as ternary ?

you could, but it wouldn't really be useful / a good idea (IMO).

$var == 1?
    ($a = 1) && ($d = 5) && ($c = 7):
    ($a = "No")
;

ternary statements are really only useful when there is only_one thing to do for each operand (and, there's a good argument for not "nesting" statements as well).

Mad_T;11003927 wrote:

The "mysql_connect SERVER A" would be something like :
mysql_connect("localhost","mysql_user","mysql_pwd");

So can I do :

$var = (isset($argv[1])) ? 'mysql_connect("localhost","mysql_user","mysql_pwd");' : 'mysql_connect("remotehost","mysql_user","mysql_pwd");'; 

yes (again, fixing typos):

$var = ( isset($argv[1]) ) ?
    (mysql_connect( "localhost","mysql_user","mysql_pwd" )): 
    (mysql_connect( "remotehost","mysql_user","mysql_pwd" ))
; 

(I've found that indenting ternary statements really helps remind you how they're going to work)

[NogDog]

While it is possible to chain ternary expressions together into a single "line" or play other "tricks" with them, you need to ask yourself, "why?" What do you expect to gain by doing so? When you come back to a piece of code a year from now to make an enhancement or fix a bug, which would you rather have to deal with?

$var = isset($_POST['foo']) ? (isset($_GET['bar']) ? $_GET['bar'] : (isset($_SESSION['fubar']) ? $_SESSION['fubar'] : 0) : 1) : 2;

...or...

$var = 2;
if(isset($_POST['foo'])) {
	if(isset($_GET['bar'])) {
		$var = _$_GET['bar'];
	}
	elseif(isset($_SESSION['fubar'])) {
		$var = 0;
	}
	else {
		$var = 1;
	}
}

And if you think the one-liner will provide some sort of performance boost, you are likely mistaken. (It seldom pays to try to out-think the compiler. 😉 )

So my general rule of thumb is to only use ternary expressions in very simple cases where it is easy to see what they are doing, and otherwise use more clearly expressed techniques. (At least one of the developers I work with has a different version of that rule: never use ternary expressions. 🙂 )

[Derokorian]

Personally I think ternary is good for intializing local variables to external data. If I ever want something to happen or multiple things to happen based on a comparison then I use a regular if/else:

// initializing GET
$page = isset($_GET['page']) ? $_GET['page'] : NULL;
if( is_null($page) ) {
   trigger_error('No page specified');
}

// initializing post
$data = array();
$data['email'] = isset($_POST['email']) ? $_POST['email'] : NULL;
$data['pass'] = isset($_POST['pass']) ? $_POST['pass'] : NULL;
if( in_array(NULL,$data) ) {
   trigger_error('Some required fields are missing');
   display_form();
}

See how assignment is through ternary, but then doing something is in a regular if. ESPECIALLY when more than one thing is to happen.

Just my 2 cents. I try not to use ternary except for simple things, and I rarely ever nest them (sometimes I do, so hate me!)

[Bonesnap]

I generally follow the same principles as Derokorian.