Regular expression to search for digits after a decimal place - regex

Question

I'm trying to write a regular expression that can match a decimal (and the digits after) of a dollar value. For example, I want to match $1.00 , $1,100.89 (includes values in the thousands with commas). It cannot match any digits that are not preceded by a $ character. There values are also not the only pieces of text in this file.
So far, I've tried a few things that haven't quite gotten me there:
\.+[\d]+ (highlights the decimal and every digit after the decimal point, but not what we want because it includes non-dollar values like 1.00)
\$+[\d+\.]+ highlights the whole value of the dollar except the 1,250
(\$\d+\.+\d+)|\$\d+\,+\d+\.+\d+ highlights the whole value of anything with a dollar sign
Anyone have an idea?

Answer 1

I looked at your problem and I believe I have a solution.
You could use the regex below to search for the last two decimals.
^\$[\d,]+\.((?:\d){2})
You can see it in action here

Answer 2

Use:
^\$[\d,]+\.(\d\d)$
Explanation:
^ # beginning of string
\$ # $ sign
[\d,]+ # 1 or more digit or comma
\. # a dot
(\d\d) # group 1, 2 digits
$ # end of string
var test = [
'$100.00',
'$1,100.89',
'$123',
'123.45',
];
console.log(test.map(function (a) {
m = a.match(/^\$[\d,]+\.(\d\d)$/);
if (m)
return a + ' : ' + m[1];
else
return a + ' : no match';
}));

Answer 3

You could use the non matching group selector (?:) to isolate only the group you want. I've come up with this regex and it seams to do what you are looking for
^(?:\$[,\d]+)(?:\.([\d]{2}))
const regex = /^(?:\$[,\d]+)(?:\.([\d]{2}))/;
const values = [
'$100.00',
'$99.99',
'$1,354.92'
];
const result = values.map(item => regex.exec(item)[1]);
console.log(result);
You could test more cases here
EDIT :
Here is an example on how to replace only the last digit.
I'm using the same concept as the other one, only this time i'm not keeping the digit. I'm going to use $1 to get the group i want in the new string.
const regex = /^(\$[,\d]+)\.(?:[\d]{2})/;
const values = [
'$100.00',
'$99.99',
'$1,354.92'
];
const result = values.map(item => item.replace(regex, '$1.50'));
console.log(result);
Notice here that the $1 in the replace function refer to the first group matching group of the regex. This way, we can get it back an "insert" it into our final string.
Here I've choosen .50 as a replace string, but you could use what ever.
P.S. I know this might be confusing because we are talking about dollar, so here is an example where we replace the final digit with a word.
const regex = /^(\$[,\d]+)\.(?:[\d]{2})/;
const values = [
'$100.00',
'$99.99',
'$1,354.92'
];
const result = values.map(item => item.replace(regex, '$1 this is a word'));
console.log(result);