Match key-value pattern regex

Question

I am making a key-value parser where the input string takes the form of key:\"value\",key2:\"value\". Keys can contain the characters a-z, A-Z

Answer 1

You could use the below regex to get the key value pair.

([a-zA-Z0-9]+):"(.*?)(?

OR

([a-zA-Z0-9]+):"(.*?)"(?=,[a-zA-Z0-9]+:"|$)

DEMO

Java regex would be,

"([a-zA-Z0-9]+):\"(.*?)(?

(? negative lookbehind asserts that the double quotes won't be preceeded by a backslash character. In java, to match a backslash character, you need to escape the backslash in your pattern exactly three times, ie, \\\\

DEMO

String s = "joe:\"Look over there\\, it's a shark!\",sam:\"I like fish.\"";

Matcher m = Pattern.compile("([a-zA-Z0-9]+):\"(.*?)(? " + m.group(2));
    }
}

Output:

joe --> Look over there\, it's a shark!
sam --> I like fish.

OR

String s = "joe:\"Look over there\\, i\\\"t's a shark!\",sam:\"I like fish.\"";

Matcher m = Pattern.compile("([a-zA-Z0-9]+):\"((?:\\\\\"|[^\"])*)\"").matcher(s);
    while(m.find())
    {
        System.out.println(m.group(1) + " --> " + m.group(2));
    }
}

Output:

joe --> Look over there\, i\"t's a shark!
sam --> I like fish.