PHP Replace {var['key']} in string with array variable

Question

I want to replace not only simple variables but also array ones. There is an answer of Alex Howansky about replace for simple variables:

$str = 'this is {TEST} a {THING} to test and a {array["key"]} var';

$TEST = 'one';
$THING = 'two';

$result = preg_replace('/\{([A-Z]+)\}/e', "$$1", $str);

It's work fine for {TEST} an {THING}.

For call variable variable for array I need ${$array}['key'] (https://stackoverflow.com/a/20216265/1056384). So I have tried to do second pass:

$result = preg_replace('/\{([a-z]+)\["([a-z]+)"\]\}/', "$\{$$1\}["$2"]", $result);

But in the output I have get the string $\{$array\}["key"] instead of value of $array["key"].

How to replace substrings in template with array variables?

Normally to interpolate an array, you have to surround it in curly braces, e.g. "Your name is {$names['key']}" but I can't get the interpolation to work inside preg_replace. This is as close as I've gotten, but it's still giving me an error PHP Parse error: syntax error, unexpected '1' (T_LNUMBER), expecting variable (T_VARIABLE) or '$' Maybe this will point you in the right direction: $result = preg_replace('/\{([a-z]+)\["([a-z]+)"\]\}/', "{$$1['$2']}", $result); — Kita
– Kita, Commented Aug 2, 2017 at 20:48
@AbraCadaver stackoverflow.com/a/20216265/1056384 my fault i need curly braces ${$array}['key'] — vatavale
– vatavale, Commented Aug 2, 2017 at 21:01
Thank you @Kita. Maybe this will work with preg_replace_callback function. — vatavale
– vatavale, Commented Aug 2, 2017 at 21:54

AbraCadaver · Accepted Answer · 2017-08-03 14:06:06Z

1

I couldn't get it to parse correctly with just preg_replace so I used a callback:

$str = 'this is {TEST} a {THING} to test and a {array["key"]} var';

$array['key'] = 'something';

$result = preg_replace_callback('/\{([a-z]+)\["([a-z]+)"\]\}/',
                                function($m) use($array){
                                    return ${$m[1]}[$m[2]];
                                },
                                $str);

If you don't know the name of the array to pass into the function you will need to make sure it's defined in the global scope and then access it that way:

$result = preg_replace_callback('/\{([a-z]+)\["([a-z]+)"\]\}/',
                                function($m) {
                                    ${$m[1]} = $GLOBALS[$m[1]];
                                    return ${$m[1]}[$m[2]];
                                },
                                $str);

edited Aug 3, 2017 at 14:06

answered Aug 2, 2017 at 21:26

AbraCadaver

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2 Comments

vatavale Over a year ago

O! Cool. It's works with predefined name of $array. Can you propose a elegant solution for situation when we don't know the "array" name?

AbraCadaver Over a year ago

Edited with a solution if the array is global.

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