PHP: print - Manual (original) (raw)

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

print — Output a string

Description

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 thatprint only accepts a single argument and always returns1.

Parameters

expression

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

Return Values

Returns 1, always.

Examples

Example #1 print examples

`<?php
print "print does not require parentheses.";
print PHP_EOL;// No newline or space is added; the below outputs "helloworld" all on one line
print "hello";
print "world";
print PHP_EOL;

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

"This string spans\nmultiple lines. The newlines will be\noutput as well.";
print PHP_EOL;// The argument can be any expression which produces a string
$foo = "example";
print "foo is $foo"; // foo is example
print PHP_EOL;$fruits = ["lemon", "orange", "banana"];
print implode(" and ", $fruits); // lemon and orange and banana
print PHP_EOL;// Non-string expressions are coerced to string, even if declare(strict_types=1) is used
print 6 * 7; // 42
print PHP_EOL;// Because print has a return value, it can be used in expressions
// The following outputs "hello world"
if ( print "hello" ) {
echo " world";
}
print PHP_EOL;// The following outputs "true"
( 1 === 1 ) ? print 'true' : print 'false';
print PHP_EOL;
?>`

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 expressionprint(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 argumentif ( 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 runprint "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 usingvariable functions, or named arguments.

Found A Problem?

user at example dot net ¶

17 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
    }
?>

mark at manngo dot net ¶

2 years 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';    
?>

danielxmorris @ gmail dotcom ¶