print

(PHP 4, PHP 5, PHP 7, PHP 8)

print — Output a string

Description

print(string $expression): int

Outputs expression.

print is not a function but a language construct. Its argument is the expression following the print keyword, and is not delimited by parentheses.

The major differences to echo are that print only accepts a single argument and always returns 1.

Parameters

expression: The expression to be output. Non-string values will be coerced to strings, even when the strict_types directive is enabled.

Return Values

Returns 1, always.

Examples

Example #1 print examples

<?php
print "print does not require parentheses.";

/ No newline or space is added; the below outputs "helloworld" all on one line
print "hello";
print "world";

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

print "This string spans\nmultiple lines. The newlines will be\noutput as well.";

/ The argument can be any expression which produces a string
$foo = "example";
print "foo is $foo"; / foo is example

$fruits = ["lemon", "orange", "banana"];
print implode(" and ", $fruits); / lemon and orange and banana

/ Non-string expressions are coerced to string, even if declare(strict_types=1) is used
print 6 * 7; / 42

/ Because print has a return value, it can be used in expressions
/ The following outputs "hello world"
if ( print "hello" ) {
    echo " world";
}

/ The following outputs "true"
( 1 === 1 ) ? print 'true' : print 'false';
?>

Notes

Note: Using with parentheses

Surrounding the argument to print with parentheses will not raise a syntax error, and produces syntax which looks like a normal function call. However, this can be misleading, because the parentheses are actually part of the expression being output, not part of the print syntax itself.

<?php print "hello"; / outputs "hello" print("hello"); / also outputs "hello", because ("hello") is a valid expression print(1 + 2) * 3; / outputs "9"; the parentheses cause 1+2 to be evaluated first, then 3*3 / the print statement sees the whole expression as one argument if ( print("hello") && false ) { print " - inside if"; } else { print " - inside else"; } / outputs " - inside if" / the expression ("hello") && false is first evaluated, giving false / this is coerced to the empty string "" and printed / the print construct then returns 1, so code in the if block is run ?>

When using print in a larger expression, placing both the keyword and its argument in parentheses may be necessary to give the intended result:

<?php if ( (print "hello") && false ) { print " - inside if"; } else { print " - inside else"; } / outputs "hello - inside else" / unlike the previous example, the expression (print "hello") is evaluated first / after outputting "hello", print returns 1 / since 1 && false is false, code in the else block is run print "hello " && print "world"; / outputs "world1"; print "world" is evaluated first, / then the expression "hello " && 1 is passed to the left-hand print (print "hello ") && (print "world"); / outputs "hello world"; the parentheses force the print expressions / to be evaluated before the && ?>

Note: Because this is a language construct and not a function, it cannot be called using variable functions, or named arguments.

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User Contributed Notes 3 notes

down

user at example dot net ¶

16 years ago

Be careful when using print. Since print is a language construct and not a function, the parentheses around the argument is not required.
In fact, using parentheses can cause confusion with the syntax of a function and SHOULD be omited.

Most would expect the following behavior:
<?php
    if (print("foo") && print("bar")) {
        / "foo" and "bar" had been printed
    }
?>

But since the parenthesis around the argument are not required, they are interpretet as part of the argument.
This means that the argument of the first print is

    ("foo") && print("bar")

and the argument of the second print is just

    ("bar")

For the expected behavior of the first example, you need to write: 
<?php
    if ((print "foo") && (print "bar")) {
        / "foo" and "bar" had been printed
    }
?>

down

danielxmorris @ gmail dotcom ¶

16 years ago

I wrote a println function that determines whether a \n or a <br /> should be appended to the line depending on whether it's being executed in a shell or a browser window.  People have probably thought of this before but I thought I'd post it anyway - it may help a couple of people.

<?php
function println ($string_message) {
    $_SERVER['SERVER_PROTOCOL'] ? print "$string_message<br />" : print "$string_message\n";
}
?>

Examples:

Running in a browser:

<?php println ("Hello, world!"); ?>
Output: Hello, world!<br />

Running in a shell:

<?php println ("Hello, world!"); ?>
Output: Hello, world!\n

down

mark at manngo dot net ¶

1 year ago

The other major difference with echo is that print returns a value, even it’s always 1.

That might not look like much, but you can use print in another expression. Here are some examples:

<?php
    rand(0,1) ? print 'Hello' : print 'goodbye';
    print PHP_EOL;
    print 'Hello ' and print 'goodbye';
    print PHP_EOL;
    rand(0,1) or print 'whatever';
?>

Here’s a more serious example:

<?php
    function test() {
        return !!rand(0,1);
    }
    test() or print 'failed';    
?>

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print

Description

Parameters

Return Values

Examples

Notes

See Also

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User Contributed Notes 3 notes