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このドキュメントでは、 php中国語ネットマニュアル リリース
(PHP 4, PHP 5)
echo — 输出一个或多个字符串
$arg1
[, string $...
] )输出所有参数。
echo 不是一个函数(它是一个语言结构), 因此你不一定要使用小括号来指明参数,单引号,双引号都可以。 echo (不像其他语言构造)不表现得像一个函数, 所以不能总是使用一个函数的上下文。 另外,如果你想给 echo 传递多个参数, 那么就不能使用小括号。
echo 也有一个快捷用法,你可以在打开标记前直接用一个等号。在 PHP 5.4.0 之前,必须在php.ini 里面启用 short_open_tag 才有效。
I have <?=$foo?> foo.
arg1
要输出的参数
...
没有返回值。
Example #1 echo 例子
<?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
$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.' . "\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 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
?>
Note: 因为是一个语言构造器而不是一个函数,不能被 可变函数 调用。