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explode> <crypt
[edit] Last updated: Fri, 25 Jan 2013

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echo

(PHP 4, PHP 5)

echoOutput one or more strings

reject note Description

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.

reject note Parameters

arg1

The parameter to output.

...

reject note Return Values

No value is returned.

reject note Examples

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

// 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
?>

reject note Notes

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

reject note See Also



explode> <crypt
[edit] Last updated: Fri, 25 Jan 2013
 
reject note add a note add a note User Contributed Notes echo - [8 notes]
up
1
nikolaas dot mennega at links dot com dot au
5 years ago
hemanman at gmail dot com, the problem is that func() doesn't actually return a value (string or otherwise), so the result of echoing func() is null.

With the comma version, each argument is evaluated and echoed in turn: first the literal string (simple), then func(). Evaluating a function call obviously calls the function (and in this case executes its own internal echo), and the result (null) is then echoed accordingly. So we end up with "outside func() within func()" as we would expect.

Thus:

<?php
echo "outside func ()\n", func ();
?>

effectively becomes:

<?php
echo "outside func ()\n";
//func ()
{
echo
"within func ()\n";
}
echo
'';
?>

The dot version is different: there's only one argument here, and it has to be fully evaluated before it can be echoed as requested. So we start at the beginning again: a literal string, no problem, then a concatenator, then a function call. Obviously the function call has to be evaluated before the result can be concatenated with the literal string, and THAT has to happen BEFORE we can complete the echo command. But evaluating func() produces its own call to echo, which promptly gets executed.

Thus:

<?php
echo "outside func ()\n" . func ();
?>

effectively becomes:

<?php
//func ()
{
echo
"within func ()\n";
}
echo
"outside func ()\n" . '';
?>
up
3
Jakob Thomsen
4 years ago
A way to color your echo output is to use shell_exec and the echo command (this only works on Linux/bash) in the following way:

<?php
echo shell_exec('echo "\e[0;31m Red color \e[0;32mGreen color \e[0m No color "');
?>

See http://wiki.archlinux.org/index.php/Color_Bash_Prompt for more colors and other options.
up
0
ximlabz at gmail dot com
1 year ago
A remedy to the problems caused by different management of returns between different platforms you can use the predefined constant PHP_EOF as the second parameter:

<?php
$foo
= "foo";
$bar = "bar";

echo
"Foo is $foo", PHP_EOL;
echo
"Bar is $bar";

// is the same as using:

echo "Foo is $foo\n";
echo
"Bar is $bar";

// but here only for UNIX-like platforms
?>
up
0
gbarros at yahoo-inc dot com
2 years ago
just banged my head on this missing bits on the manual.
When using the <<< method, the array keys does not require any kind of quotes.

<?php
foreach ( $data as $i ){
echo <<< END
<tr>
  <td>
$i[date]</td>
  <td>
$i[name]</td>
 </tr>
END;
}
?>

Let's hope you don't have any <?php echo $klingonships['th\'bl][ath']?> kind of array :)
up
0
Jason Carlson - SiteSanity
7 years ago
In response to Ryan's post with his echobig() function, using str_split wastes memory resources for what you are doing.

If all you want to do is echo smaller chunks of a large string, I found the following code to perform better and it will work in PHP versions 3+

<?php
function echobig($string, $bufferSize = 8192)
{
 
// suggest doing a test for Integer & positive bufferSize
 
for ($chars=strlen($string)-1,$start=0;$start <= $chars;$start += $bufferSize) {
    echo
substr($string,$start,$buffer_size);
  }
}
?>
up
0
ryan at wonko dot com
7 years ago
Due to the way TCP/IP packets are buffered, using echo to send large strings to the client may cause a severe performance hit. Sometimes it can add as much as an entire second to the processing time of the script. This even happens when output buffering is used.

If you need to echo a large string, break it into smaller chunks first and then echo each chunk. The following function will do the trick in PHP5:

<?php
function echobig($string, $bufferSize = 8192)
{
   
$splitString = str_split($string, $bufferSize);

    foreach(
$splitString as $chunk)
        echo
$chunk;
}
?>
up
-1
fire at dls dot net
1 year ago
Pay attention to this part of the documentation:
echo() (unlike some other language constructs) does not behave like a function, so it cannot always be used in the context of a function

I was trying to make certain that I was detecting errors and was trying code like this:

@alwaysFails() or echo('Surprise! It failed again');

This error was generated:
[29-Jul-2011 12:56:19] PHP Parse error:  syntax error, unexpected T_ECHO in /Applications/MAMP/test.php on line 12

Changing to die(), print() or a function I defined worked fine. Beware of this limitation of echo.
up
-1
zombie)at(localm)dot(org)
10 years ago
[Ed. Note: During normal execution, the buffer (where echo's arguments go) is not flushed (sent) after each write to the buffer. To do that you'd need to use the flush() function, and even that may not cause the data to be sent, depending on your web server.]

Echo is an i/o process and i/o processes are typically time consuming. For the longest time i have been outputting content by echoing as i get the data to output. Therefore i might have hundreds of echoes in my document. Recently, i have switched to concatenating all my string output together and then just doing one echo at the end. This organizes the code more, and i do believe cuts down on a bit of time. Likewise, i benchmark all my pages and echo seems to influence this as well. At the top of the page i get the micro time, and at the end i figure out how long the page took to process. With the old method of "echo as you go" the processing time seemed to be dependent on the user's net connection as well as the servers processing speed. This was probably due to how echo works and the sending of packets of info back and forth to the user. One an one script i was getting .0004 secs on a cable modem, and a friend of mine in on dialup was getting .2 secs. Finally, to test that echo is slow; I built strings of XML and XSLT and used the PHP sablotron functions to do a transformation and return a new string. I then echoed the string. Before the echo, the process time was around .025 seconds and .4 after the echo. So if you are big into getting the actual processing time of your scripts, don't include echoes since they seem to be user dependent. Note that this is just my experience and it could be a fluke.

 
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