How to echo function php?

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

echo — Output one or more strings

Description

echo(string ...$expressions): void

Outputs one or more expressions, with no additional newlines or spaces.

echo is not a function but a language construct. Its arguments are a list of expressions following the echo keyword, separated by commas, and not delimited by parentheses. Unlike some other language constructs, echo does not have any return value, so it cannot be used in the context of an expression.

echo also has a shortcut syntax, where you can immediately follow the opening tag with an equals sign. This syntax is available even with the short_open_tag configuration setting disabled.

The major differences to print are that echo accepts multiple arguments and doesn't have a return value.

Parameters

One or more string expressions to output, separated by commas. Non-string values will be coerced to strings, even when the strict_types directive is enabled.

Return Values

No value is returned.

Examples

Example #1 echo examples

echo "echo does not require parentheses.";// 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.', "\n";
echo 'This ' . 'string ' . 'was ' . 'made ' . 'with concatenation.' . "\n";// No newline or space is added; the below outputs "helloworld" all on one line
echo "hello";
echo "world";// Same as above
echo "hello", "world";

echo

Notes

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

Note: Using with parentheses

Surrounding a single argument to echo 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 echo syntax itself.

echo "hello";
// outputs "hello"echo("hello");
// also outputs "hello", because ("hello") is a valid expressionecho(1 + 2) * 3;
// outputs "9"; the parentheses cause 1+2 to be evaluated first, then 3*3
// the echo statement sees the whole expression as one argumentecho "hello", " world";
// outputs "hello world"echo("hello"), (" world");
// outputs "hello world"; the parentheses are part of each expressionecho("hello", " world");
// Throws a Parse Error because ("hello", " world") is not a valid expression
?>

Tip

Passing multiple arguments to echo can avoid complications arising from the precedence of the concatenation operator in PHP. For instance, the concatenation operator has higher precedence than the ternary operator, and prior to PHP 8.0.0 had the same precedence as addition and subtraction:

// Below, the expression 'Hello ' . isset($name) is evaluated first,
// and is always true, so the argument to echo is always $name
echo 'Hello ' . isset($name) ? $name : 'John Doe' . '!';// The intended behaviour requires additional parentheses
echo 'Hello ' . (isset($name) ? $name : 'John Doe') . '!';// In PHP prior to 8.0.0, the below outputs "2", rather than "Sum: 3"
echo 'Sum: ' . 1 + 2;// Again, adding parentheses ensures the intended order of evaluation
echo 'Sum: ' . (1 + 2);

If multiple arguments are passed in, then parentheses will not be required to enforce precedence, because each expression is separate:

echo "Hello ", isset($name) ? $name : "John Doe", "!";

echo

See Also

• print - Output a string
• printf() - Output a formatted string
• flush() - Flush system output buffer
• Ways to specify literal strings

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.

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.

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:

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

vs

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).

retrobytespr at mail dot com ¶

7 months ago

If you have a large block of text, say your blog or something includes code examples, you may use the <<< operator (?) to define the start and end of your block to be echoed out. For instance:

echo <<< JAVASCRIPT

function convertTroyOuncesToGrams(troyOunce) {
    return troyOunce / 31.1034768;
}JAVASCRIPT; # End of block?>

You may also embed PHP strings and other simple scalars into your blocks of text, for example:

$troyOunceAsGrams = 31.1034768;

echo <<< JAVASCRIPT

t3tesla at gmail dot com ¶

1 year ago

We can use the 'echo' shortcut syntax with the conditional operator (expr1) ? (expr2) : (expr3)

$some_var = 10;
?>
Back to html :


: "class2"?>">Some text.

Will give : 

Some text.

$some_var = 4;
?>


: "class2"?>">Some text.

Will give : 

Some text.

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):

echo "

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