How can I use regex to get all the characters after a specific character, e.g. comma (",")

You don't need regex to do this. Here's an example :

var str = "'SELECT___100E___7',24";
var afterComma = str.substr(str.indexOf(",") + 1); // Contains 24 //

Short answer

Either:

• ,[\s\S]*$ or ,.*$ to match everything after the first comma (see explanation for which one to use); or

• [^,]*$ to match everything after the last comma (which is probably what you want).

You can use, for example, /[^,]*/.exec(s)[0] in JavaScript, where s is the original string. If you wanted to use multiline mode and find all matches that way, you could use s.match(/[^,]*/mg) to get an array (if you have more than one of your posted example lines in the variable on separate lines).

Explanation

• [\s\S] is a character class that matches both whitespace and non-whitespace characters (i.e. all of them). This is different from . in that it matches newlines.
• [^,] is a negated character class that matches everything except for commas.
• * means that the previous item can repeat 0 or more times.
• $ is the anchor that requires that the end of the match be at the end of the string (or end of line if using the /m multiline flag).

For the first match, the first regex finds the first comma , and then matches all characters afterward until the end of line [\s\S]*$, including commas.

The second regex matches as many non-comma characters as possible before the end of line. Thus, the entire match will be after the last comma.

[^,]*$

might do. (Matches everything after the last comma).

Explanation: [^,] matches every character except for ,. The * denotes that the regexp matches any number of repetition of [^,]. The $ sign matches the end of the line.