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# echo

(PHP 3, PHP 4, PHP 5 )

echo -- Output one or more strings

## Description

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

Outputs all parameters.

echo() is not actually a function (it is a language construct) so you are not required to use parentheses with it. In fact, if you want to pass more than one parameter to echo, you must not enclose the parameters within parentheses.

示範 1.echo() examples
`<?php echo "Hello World"; echo "This spans multiple lines. The newlines will be output as well"; echo "This spans\nmultiple lines. The newlines will be\noutput 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 $bar = array("value" => "foo"); echo "this is {$bar['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.' . "\n"; echo <<<END This uses the "here document" syntax to output multiple lines with $variable interpolation. Note that the here document terminator must appear on a line with just a semicolon. no extra whitespace! END; // Because echo is not a function, following code is invalid. ($some_var) ? echo 'true' : echo 'false'; // However, the following examples will work: ($some_var) ? print('true'): print('false'); // print is a function echo $some_var ? 'true': 'false'; // changing the statement around ?>`

echo() also has a shortcut syntax, where you can immediately follow the opening tag with an equals sign. This short syntax only works with the short_open_tag configuration setting enabled.

`I have <?=$foo?> foo.`

For a short discussion about the differences between print() and echo(), see this FAQTs Knowledge Base Article: http://www.faqts.com/knowledge_base/view.phtml/aid/1/fid/40

> 備注:由於這是一個語言結構、而不是函數，所以不能以變數函數的方式來呼叫。

See also print(), printf(), and flush().

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