Is there any way to force a string to evaluate (as a double quoted string/heredoc would)?
For example is there some clean way of doing this:
<?php
$mystring = <<<'MS'
hello {$adjectives['first']} world
MS;
$adjectives = array('first'=>'beautiful');
// here I want to print 'hello beautiful world'
// instead of 'hello {$adjectives['first']} world'
echo evaluate($mystring); // evaluate is not a real function
?>
You can use eval since you plan to use it only on strings you created your self. Don't ever use eval if the string (or the replacements) are outside your control.
$mystring = <<<'MS'
hello %s world
MS;
$adjectives = array('first'=>'beautiful');
eval('$parsed = ' . json_encode($mystring) . ';');
echo($parsed);
See http://sandbox.onlinephpfunctions.com/code/b1f6afc24efbc685f738dc1e7fd3668afdf5b7d0
As suggested by NATH, sprintf would do the job for you without the security implications of eval
$mystring = <<<'MS'
hello %s world
MS;
$adjectives = array('first' => 'beautiful');
echo sprintf($mystring, $adjectives['first']);
I would strongly advise to avoid using eval(). I think it's dangerous, slow, and a bad practice in general. Using vsprintf() instead should do the trick for you.
// Use argument swapping (%1\$s instead of %s) to explicitly specify which
// position in the array represents each value. Useful if you're swapping out
// multiple values.
$mystring = <<<MS
hello %1\$s world
MS;
$adjectives = array('first'=>'beautiful');
echo vsprintf($mystring, $adjectives);
Yes and you nearly got it.
Look at this example for eval @ php.net
<?php
$string = 'cup';
$name = 'coffee';
$str = 'This is a $string with my $name in it.';
echo $str. "\n";
eval("\$str = \"$str\";");
echo $str. "\n";
?>
Please note however, that using eval is dangerous and opens the possibility of all kind of attacks if not handled properly.
Maybe a better solution would be to use place holders of some kind.
$str = "This is a __first__ world";
$adjectives = array('first'=>'beautiful');
foreach ($adjectives as $k=>$v) {
$str = preg_replace('/__'.$k.'__/', $v, $str);
}
echo $str;
$mySytringafter$adjectiveshas been defined?sprintf?