Is it better to concatenate a variable (say, $name) into an existing string (say, $string) like this:
$string='Hi, my name is '.$name
or to embed the variable in the string like this:
$string="Hi, my name is $name";
or is it better to use a function like this:
$string=sprintf("Hi, my name is %s",$name);
Which is better in terms of processor time/efficiency?
Just use . for concatenating.
And you missed out the $personCount increment!
while ($personCount < 10) {
$result .= $personCount . ' people';
$personCount++;
}
echo $result;
The . operator is the concatenation operator. Your first example only works because the echo 'function' (technically it's a language construct, but lets not split hairs) accepts more than one parameter, and will print each one.
So your first example is calling echo with more than one parameter, and they are all being printed, vs. the second example where all the strings are being concatentated and that one big string is being printed.
It's perfectly fine. It's also the convention I use: single quotes for strings in EL. It's not only better readable, but it's also friendly for syntax highlighting.
Using double quotes is valid, but harder to interpret when nested in a HTML attribute which is by itself also double quoted.
You could save that kind of string by modifying it on the server side before output, like this:
html_content = "<?=addslashes($string);?>"
The method addslashes($string) would then escape any double quotes at runtime before feeding it to the JavaScript variable.
Everyone who did the test concluded that using single quotes is marginally better performance wise. In the end single quotes result in just a concatenation while double quotes forces the interpreter to parse the complete string for variables.
However the added load in doing that is so small for the last versions of PHP that most of the time the conclusion is that it doesn't really matter.
So for the performance people: use single quotes. For the "i like my code readable"-people: double quotes are a lot better for the legibility, as Flavius Stef already pointed out.
Edit: One thing though - If you are going to use a a single dollar in your string without a variable, use single quotes for sure! (http://www.weberdev.com/get_example-3750.html points out that it will take 4 times longer to parse those strings)