Prepend Character To String In Jquery With Regular Expression

I'm trying to add a character to the beginning of certain strings with Regular Expressions but am very new to it and can't seem to find an answer for what I'm looking for. I have s

Solution 1:

I believe this handles all possibilities:

"111 Above 1499 and below 14930 and $100".replace(/([^$]|^)(\b\d+)/g, "$1$$$2")
> "$111 Above $1499 and below $14930 and $100"

To replace the text in Jquery:

$(this).text(function(i, t) { return t.replace(...above stuff...) })

http://jsfiddle.net/k7XJw/1/

To ignore numbers is parentheses,

str = "111 Above 1499 and below 14930(55) and $100 and (1234) and (here 123) and (123 there)"
str.replace(/([^$(]|^)(\b\d+\b)(?!\))/g, "$1$$$2")
> "$111 Above $1499 and below $14930(55) and $100 and (1234) and (here 123) and (123 there)"

Solution 2:

For simple strings like the one you posted a lookahead regex and replace will work. Basically telling the regex to find the first number in a string (but dont consume it) and then prepend a dollar sign. For multiple numbers in the same string you will have to tweak the regex.

var s = "before 1900"
s=s.replace(/(?=[0-9])/,"$");
console.log(s);

Modified to support multiple occurences. It looks for any number preceeded by a whitespace and then prepends the dollar sign to that number.

Plunker example

var s = "before 1900 and 2130 and (1900)"
s=s.replace(/\s(?=\d)/g," $");
console.log(s);