(PHP 4 >= 4.1.0, PHP 5, PHP 7)
vprintf — Output a formatted string
$format
, array $args
)
Display array values as a formatted string according to
format (which is described in the documentation
for sprintf()).
Operates as printf() but accepts an array of arguments, rather than a variable number of arguments.
Returns the length of the outputted string.
Example #1 vprintf(): zero-padded integers
<?php
vprintf("%04d-%02d-%02d", explode('-', '1988-8-1')); // 1988-08-01
?>
If, instead of an array, you pass an object PHP will automatically cast the object as an array so you can use it directly in vprintf.
<?php
$object = new stdClass();
$object->Property1 = 'Value 1';
$object->Property2 = 'Value 2';
vprintf('%-20s %-20s', $object);
/* will output
Value 1 Value 2
*/
?>
Another way to display arrays is use an array_walk(). This can be useful inline echo/print where a foreach wouldn't work, e.g.
<?php
echo "These errors: ", (unset)array_walk($msgs, function($a) { echo "<p>$a</p>"; } ), "must be corrected.";
?>
For blocks of text, sprintf() is slow according to my tests.
Also, having the mapping between place-holders and the list of actual variables or datastructures often makes this code difficult to read. But the printf() family are widely supported and have a huge range of nice features. Performance is a cold mistress though!
From an ease-of-reading and maintenance, debugging point of view, I much prefer HEREDOC and "...{$variable}..." methods.
For a block of HTML markup with place holders, the fastest by far was:-
?>
<div> markup etc<?= $variable ?>more markup
<?
My tests comprised 20 runs of a loop of 1 million iterations with output buffering, ditching the buffer on each loop.
The timings ranged from average 2.1msec/million repetitions for the <?= $var ?> method up to 7.6msec/million using printf().
I'll try some benchmarking tools too, since I just wrote this myself and it could be introducing bias, but they've run on dev servers with low load.
Hopefully interesting.
To toolofthesystem at gmail dot com:
You don't need to use output buffering with vprintf() because you can use vsprintf(), which has the same functionality as vprintf(), except that it returns the resulting string instead of outputting it.
This function comes useful sometimes when trying to list information returned from MySQL:
function print_sql($query,$printf){
$sql_sql = mysql_query($query);
while($sql = mysql_fetch_row($sql_sql)){
vprintf($printf,$sql);
}
}
Unfortunately, this seems to sneak its way past output buffering when I tried creating an argument to allow it to be contained in a returned string... either that or I didn't do it right.
i know that you can use %1$s or %3$s to select the first or third string but how can you or can you use array names to select it
something like %'user'$s $'email'$s
i tend to add things to my databases over time and this could save loads of recoding
<?php
$string = 'The site runs on PHP '.phpversion();
preg_match('/php ((\d)\.\d\.\d+)/i',$string,$matches);
print_r($matches);
vprintf('Match: %s<br /> Version %s; Major:%d.',$matches);
?>
output:
Array ( [0] => PHP 5.2.5 [1] => 5.2.5 [2] => 5 )
Match: PHP 5.2.5 Version 5.2.5; Major:5.
For preg_match:
If matches is provided, then it is filled with the results of search. $matches[0] will contain the text that matched the full pattern, $matches[1] will have the text that matched the first captured parenthesized subpattern, and so on.
