Question

Consider the following string:

$text = "Dat foo 13.45 and $600 bar {70} and {8}";

I need to label all numbers in $text, except for when they are between curly braces. I now have this:

echo preg_replace("([0-9]+(?:\.[0-9]+)?)","{NUMBER:$0}",$tweet);

which outputs:

Dat foo {NUMBER:13.45} and ${NUMBER:600} bar {{NUMBER:70}} and {{NUMBER:8}}

However, the desired output is:

Dat foo {NUMBER:13.45} and ${NUMBER:600} bar {70} and {8}

where numbers between { and } are ignored. Is it possible to expand the regex to ommit curly braces or is another solution needed here?

Any help would be greatly appreciated 🙂

Answer 1

Try using lookaheads/lookbehinds to find numbers without {}.

NOTE: Make sure to enclose your regex in delimiters (such as /).

echo preg_replace("/(?<!{)([0-9]+(?:\.[0-9]+)?)(?!})/","{NUMBER:$0}",$tweet);

DEMO: http://codepad.org/7ai0px2i

(?<!{) means “not preceded by a {“, and (?!}) means “not followed by a }“.