Regex to match “{number}”

Question

I need to replace \"{Z}\" with \"test(Z)\" where Z is always an unsigned integer using PHP and regular expressions (unless there\'s a faster way?).

$code=\'{         


        

Answer 1

$code = preg_replace('/\{(\d+)\}/', 'test($1)', $code);

In my experience, preg_replace is much faster than any method of doing replacements using str_replace or strtr.

Answer 2

The missing line is this:

$code = preg_replace('/{([0-9]+)}/', 'test($1)', $code);

How it works:

{       match a literal {
(       start a capturing group
[0-9]+  one or more digits in 0-9
)       end the capturing group
}       match a literal }

The $1 in the replacement string refers to the string captured by the first (and only) capturing group.