concatenation

[Anon]

I see a lot of code posted here using the concatenation oprator('.') What is the practical difference between these two examples?

$name = 'John';
$var = "My name is $name Smith";
$var = "My name is " . $name . " Smith";

Are there performance issues with having a varible within the qoutes?

[lucianoes]

I am a newbie and cannot tell for sure, but my own experience tells me it is not mandatory. It is very useful, though, when you have a particularly busy line of code, with many variables and text together, and want to make everything look clearer.

[Anon]

Style, generally. PHP3 tended to come to grief on variables "inside $double[2] quotes" when they started getting fancy, so the latter construct was required on a fairly regular basis.

There is a slight performance issue; it's not so much between having variables within the quotes versus not having variables, but between using single-quoted strings versus double-quoted strings. Double-quoted strings are checked for variables while single-quoted strings aren't - there is some overhead associated with the checking.

But if you have an optimiser installed in your build of PHP, such differences tend to come out in the wash anyway, and it returns to a matter of style (and legibility!).