echo(3) [php man page]

ECHO(3) 								 1								   ECHO(3)

echo - Output one or more strings

SYNOPSIS

       void echo (string  $arg1, [string  $...])

DESCRIPTION

	Outputs all parameters.

       echo  is not actually a function (it is a language construct), so you are not required to use parentheses with it.  echo (unlike some other
       language constructs) does not behave like a function, so it cannot always be used in the context of a function. Additionally, if  you  want
       to pass more than one parameter to echo, the parameters must not be enclosed within parentheses.

       echo  also has a shortcut syntax, where you can immediately follow the opening tag with an equals sign. Prior to PHP 5.4.0, this short syn-
       tax only works with the short_open_tag configuration setting enabled.

       I have <?=$foo?> foo.

PARAMETERS

	      o $arg1
		- The parameter to output.

	      o $...
		-

RETURN VALUES

	No value is returned.

EXAMPLES

       Example #1

	      echo examples

	      <?php
	      echo "Hello World";

	      echo "This spans
	      multiple lines. The newlines will be
	      output as well";

	      echo "This spans
multiple lines. The newlines will be
output as well.";

	      echo "Escaping characters is done "Like this".";

	      // You can use variables inside of an echo statement
	      $foo = "foobar";
	      $bar = "barbaz";

	      echo "foo is $foo"; // foo is foobar

	      // You can also use arrays
	      $baz = array("value" => "foo");

	      echo "this is {$baz['value']} !"; // this is foo !

	      // Using single quotes will print the variable name, not the value
	      echo 'foo is $foo'; // foo is $foo

	      // If you are not using any other characters, you can just echo variables
	      echo $foo;	  // foobar
	      echo $foo,$bar;	  // foobarbarbaz

	      // Some people prefer passing multiple parameters to echo over concatenation.
	      echo 'This ', 'string ', 'was ', 'made ', 'with multiple parameters.', chr(10);
	      echo 'This ' . 'string ' . 'was ' . 'made ' . 'with concatenation.' . "
";

	      echo <<<END
	      This uses the "here document" syntax to output
	      multiple lines with $variable interpolation. Note
	      that the here document terminator must appear on a
	      line with just a semicolon. no extra whitespace!
	      END;

	      // Because echo does not behave like a function, the following code is invalid.
	      ($some_var) ? echo 'true' : echo 'false';

	      // However, the following examples will work:
	      ($some_var) ? print 'true' : print 'false'; // print is also a construct, but
							  // it behaves like a function, so
							  // it may be used in this context.
	      echo $some_var ? 'true': 'false'; // changing the statement around
	      ?>

NOTES

       Note

	      Because this is a language construct and not a function, it cannot be called using variable functions.

SEE ALSO

       print(3), printf(3), flush(3), Heredoc syntax.

PHP Documentation Group 														   ECHO(3)

UNSET(3)								 1								  UNSET(3)

unset - Unset a given variable

SYNOPSIS

       void unset (mixed  $var, [mixed	$...])

DESCRIPTION

       unset(3) destroys the specified variables.

	The behavior of unset(3) inside of a function can vary depending on what type of variable you are attempting to destroy.

	If  a  globalized variable is unset(3) inside of a function, only the local variable is destroyed. The variable in the calling environment
       will retain the same value as before unset(3) was called.

       <?php
       function destroy_foo()
       {
	   global $foo;
	   unset($foo);
       }

       $foo = 'bar';
       destroy_foo();
       echo $foo;
       ?>

       The above example will output:

       bar

	To unset(3) a global variable inside of a function, then use the $GLOBALS array to do so:

       <?php
       function foo()
       {
	   unset($GLOBALS['bar']);
       }

       $bar = "something";
       foo();
       ?>

	If a variable that is PASSED BY REFERENCE is unset(3) inside of a function, only the local variable is	destroyed.  The  variable  in  the
       calling environment will retain the same value as before unset(3) was called.

       <?php
       function foo(&$bar)
       {
	   unset($bar);
	   $bar = "blah";
       }

       $bar = 'something';
       echo "$bar
";

       foo($bar);
       echo "$bar
";
       ?>

       The above example will output:

       something
       something

	If  a static variable is unset(3) inside of a function, unset(3) destroys the variable only in the context of the rest of a function. Fol-
       lowing calls will restore the previous value of a variable.

       <?php
       function foo()
       {
	   static $bar;
	   $bar++;
	   echo "Before unset: $bar, ";
	   unset($bar);
	   $bar = 23;
	   echo "after unset: $bar
";
       }

       foo();
       foo();
       foo();
       ?>

       The above example will output:

       Before unset: 1, after unset: 23
       Before unset: 2, after unset: 23
       Before unset: 3, after unset: 23

PARAMETERS

	      o $var
		- The variable to be unset.

	      o $...
		- Another variable ...

RETURN VALUES

	No value is returned.

EXAMPLES

       Example #1

	      unset(3) example

	      <?php
	      // destroy a single variable
	      unset($foo);

	      // destroy a single element of an array
	      unset($bar['quux']);

	      // destroy more than one variable
	      unset($foo1, $foo2, $foo3);
	      ?>

       Example #2

	      Using (unset) casting

	      (unset) casting is often confused with the unset(3) function.  (unset) casting serves only as a NULL-type cast, for completeness. It
	      does not alter the variable it's casting.

	      <?php
	      $name = 'Felipe';

	      var_dump((unset) $name);
	      var_dump($name);
	      ?>

	      The above example will output:

	      NULL
	      string(6) "Felipe"

NOTES

       Note

	      Because this is a language construct and not a function, it cannot be called using variable functions.

       Note

	       It is possible to unset even object properties visible in current context.

       Note

	       It is not possible to unset $this inside an object method since PHP 5.

       Note

	       When using unset(3) on inaccessible object properties, the __unset() overloading method will be called, if declared.

SEE ALSO

       isset(3), empty(3), __unset(), array_splice(3).

PHP Documentation Group 														  UNSET(3)