(PHP 4, PHP 5, PHP 7)
echo — Output one or more strings
$arg1
[, string $...
] )Outputs all parameters. No additional newline is appended.
echo is not actually a function (it is a language construct), so you are not required to use parentheses with it. echo (unlike some other language constructs) does not behave like a function, so it cannot always be used in the context of a function. Additionally, if you want to pass more than one parameter to echo, the parameters must not be enclosed within parentheses.
echo also has a shortcut syntax, where you can immediately follow the opening tag with an equals sign. Prior to PHP 5.4.0, this short syntax only works with the short_open_tag configuration setting enabled.
I have <?=$foo?> foo.
The only difference to print is that echo accepts an argument list.
arg1The parameter to output.
...
No value is returned.
Example #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
// Strings can either be passed individually as multiple arguments or
// concatenated together and passed as a single argument
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 $some_var ? 'true': 'false'; // changing the statement around
?>
Note: Because this is a language construct and not a function, it cannot be called using variable functions.
A benefit to passing in multiple arguments over using concatenation in echo regards the precedence of the period operator in PHP. If multiple arguments are passed in, then parentheses will not be required to enforce precedence:
<?php
echo "Sum: ", 1 + 2;
echo "Hello ", isset($name) ? $name : "John Doe", "!";
With concatenation, the period operator has a higher precedence than both the addition and ternary operators, and so parentheses must be used for the correct behaviour:
<?php
echo 'Sum: ' . (1 + 2);
echo 'Hello ' . (isset($name) ? $name : 'John Doe') . '!';