// Little known PHP features: calling echo with multiple parameters

First of all, many PHP newbies do not even know that echo is not a function but a language construct. This means, the following two lines of code do the same:

  echo "Hello world\n"; //because echo is NO function, brackets are not needed.
  echo("Hello world\n");

IMHO, you should use the first variant without brackets to signalize that echo is not a function1).

But even experienced developers do not know the possibility to pass more than one parameter - there is no need to concatenate strings with a dot (which may be useful in some situations). The following code does the same three times:

  $str1 = "one";
  $str2 = "two";
  $str3 = "three\n\n";
 
  //newbie style, most overhead because echo is called more often than needed
  echo $str1;
  echo $str2;
  echo $str3;
 
  //common style with concatenated string (on my machines with PHP 5.2,
  //64bit *ix, this is the fastest)
  echo $str1.$str2.$str3;
 
  //little known: pass more than one parameter (on my machines with PHP <5.1,
  //this is the fastest)
  echo $str1, $str2, $str3;

My personal experience/small note about the performance: the more variables are involved + the bigger their data is, the slower is a concatenated string in comparison to passing the vars as parameter. But the difference is getting really small on PHP >=5.2. Additionally, echo is really fast, no matter if you use concatenation or commas. Just prevent unneeded echo calls and everything is fine. :-)

1)
BTW: same with include[_once] and require[_once]

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