Parse variables within string

Question

I'm storing some strings within a *.properties file. An example of a string is:

sendingFrom=Sending emails from {$oEmails->agentName}, to {$oEmails->customerCount} people.

My function takes the value from sendingFrom and then outputs that string on the page, however it doesn't automatically parse the {$oEmails->agentName} within. Is there a way, without manually parsing that, for me to get PHP to convert the variable from a string, into what it should be?

score 4 · Accepted Answer · answered May 23 '12 at 16:57

4

If you can modify your *.properties, here is a simple solution:

# in file.properties
sendingFrom = Sending emails from %s, to %s people.

And then replacing %s with the correct values, using sprintf:

// Get the sendingFrom value from file.properties to $sending_from, and:
$full_string = sprintf($sending_from, $oEmails->agentName, $oEmails->customerCount);

It allows you to separate the logic of your app (the variables, and how you get them) from your presentation (the actual string scheme, stored in file.properties).

answered May 23 '12 at 16:57

ldiqual

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Ah, now that is a clever idea! Thank you :) – James May 23 '12 at 17:00
1

I like this method as well. If you ever change your variable names you wont have to modify your file also. – EmmanuelG May 23 '12 at 17:03
That's perfect. I have a function which outputs the message with some extra formatting. I've just used `vsprintf` to take my arguments (from 3 onwards) and output. Clean and simple. Awesome idea, thank you very much! – James May 23 '12 at 17:09

score 2 · Answer 2 · answered May 23 '12 at 17:51

Just an alternative.

$oEmails = new Emails('Me',4);
$str = 'sendingFrom=Sending emails from {$oEmails->agentName}, to {$oEmails->customerCount} people.';

// --------------

$arr = preg_split('~(\{.+?\})~',$str,-1,PREG_SPLIT_DELIM_CAPTURE);
for ($i = 1; $i < count($arr); $i+=2) {
    $arr[$i] = eval('return '.substr($arr[$i],1,-1).';');
}
$str = implode('',$arr);
echo $str;
// sendingFrom=Sending emails from Me, to 4 people.

score 1 · Answer 3 · edited May 23 '17 at 12:05

1

as others mentioned eval wouldn't be appropriate, I suggest a preg_replace or a preg_replace_callback if you need more flexibility.

preg_replace_callback('/\$(.+)/', function($m) {
     // initialise the data variable from your object  
     return $data[$m[1]];
}, $subject);

Check this link out as well, it suggests the use of strstr How replace variable in string with value in php?

edited May 23 '17 at 12:05

Community

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answered Mar 11 '14 at 08:39

filype

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score 0 · Answer 4 · answered May 23 '12 at 16:55

0

You can use Eval with all the usual security caviats

Something like.

$string = getStringFromFile('sendingFrom');

$FilledIn = eval($string);

answered May 23 '12 at 16:55

Toby Allen

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2

If only there was an `eval_vars` function. – James May 23 '12 at 17:00
2

There are plenty of security issues related to `eval`. For instance, if someone manages to modify `file.properties` he can do very bad things as php will run the code. Don't use `eval`. – ldiqual May 23 '12 at 17:03
@idiqual, thats what the security Caveats are. However just don't use it is probably a better Caveat. – Toby Allen May 23 '12 at 17:05

Parse variables within string

4 Answers4