echo

(PHP 4, PHP 5)

echoOutput one or more strings

Опис

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

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 syntax only works with the short_open_tag configuration setting enabled.

I have <?=$foo?> foo.

Параметри

arg1

The parameter to output.

...

Значення, що повертаються

Не повертає значень.

Приклади

Приклад #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
$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
?>

Примітки

Зауваження: Оскільки це є мовна конструкція, а не функція, її не можна викликати через змінні функції.

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User Contributed Notes 3 notes

up
30
pemapmodder1970 at gmail dot com
5 years ago
Passing multiple parameters to echo using commas (',')is not exactly identical to using the concatenation operator ('.'). There are two notable differences.

First, concatenation operators have much higher precedence. Referring to http://php.net/operators.precedence, there are many operators with lower precedence than concatenation, so it is a good idea to use the multi-argument form instead of passing concatenated strings.

<?php
echo "The sum is " . 1 | 2; // output: "2". Parentheses needed.
echo "The sum is ", 1 | 2; // output: "The sum is 3". Fine.
?>

Second, a slightly confusing phenomenon is that unlike passing arguments to functions, the values are evaluated one by one.

<?php
function f($arg){
 
var_dump($arg);
  return
$arg;
}
echo
"Foo" . f("bar") . "Foo";
echo
"\n\n";
echo
"Foo", f("bar"), "Foo";
?>

The output would be:
string(3) "bar"FoobarFoo

Foostring(3) "bar"
barFoo

It would become a confusing bug for a script that uses blocking functions like sleep() as parameters:

<?php
while(true){
  echo
"Loop start!\n", sleep(1);
}
?>

vs

<?php
while(true){
  echo
"Loop started!\n" . sleep(1);
}
?>

With ',' the cursor stops at the beginning every newline, while with '.' the cursor stops after the 0 in the beginning every line (because sleep() returns 0).
up
0
t3tesla at gmail dot com
1 year ago
We can use the 'echo' shortcut syntax with the conditional operator (expr1) ? (expr2) : (expr3)

<?php
$some_var
= 10;
?>
Back to html :
<p class="<?=$some_var>5 ? "class1" : "class2"?>">Some text.</p>

Will give :  <p class="class1">Some text.</p>

<?php
$some_var
= 4;
?>
<p class="<?=$some_var>5 ? "class1" : "class2"?>">Some text.</p>

Will give :  <p class="class2">Some text.</p>
up
-3
mparsa1372 at gmail dot com
1 year ago
The following example shows how to output text with the echo command (notice that the text can contain HTML markup):

<?php
echo "<h2>PHP is Fun!</h2>";
echo
"Hello world!<br>";
echo
"I'm about to learn PHP!<br>";
echo
"This ", "string ", "was ", "made ", "with multiple parameters.";
?>
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