C# regex to extract key value

Question

Is there an easy and elegant way to extract key value pairs from a string of below format?

"key1='value1' key2='value 2' key3='value3' key4='value4' key5='5555' key6='xxx666'"

My attempt resulted in this but I'm not too happy with it

var regex = new Regex(@"\'\s", RegexOptions.None);
var someString = @"key1='value1' key2='value 2' key3='value3' key4='value4' key5='5555' key6='xxx666'" + " ";

var splitArray = regex.Split(someString);

IDictionary<string, string> keyValuePairs = new Dictionary<string, string>();

foreach (var split in splitArray)
{
    regex = new Regex(@"\=\'", RegexOptions.None);

    var keyValuArray = regex.Split(split);

    if (keyValuArray.Length > 1)
    {
        keyValuePairs.Add(keyValuArray[0], keyValuArray[1]);
    }

}

Sergey Kalinichenko · Accepted Answer · 2014-11-02 14:52:41Z

7

You should be able to do it without a split, using a MatchCollection instead:

var rx = new Regex("([^=\\s]+)='([^']*)'");
var str = "key1='value1' key2='value 2' key3='value3' key4='value4' key5='5555' key6='xxx666'";
foreach (Match m in rx.Matches(str)) {
    Console.WriteLine("{0} {1}", m.Groups[1], m.Groups[2]);
}

Demo.

The heart of this solution is this regular expression: ([^=\\s]+)='([^']*)' It defines the structure of your key-value pair: a sequence of non-space characters defines the key, then there's an equal sign, followed by the value enclosed in single quotes. This solution goes through the matches in sequence, extracting keys and values, which are assigned to matching groups Group[1] and Group[2], in this order.

answered Nov 2, 2014 at 14:52

Sergey Kalinichenko

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1 Comment

Display name Over a year ago

Thanks @dasblinkenlight. That is spot on. Exactly what I was looking for. The explanation helps a lot too. Much appreciated.

Ulugbek Umirov · Accepted Answer · 2014-11-02 14:54:36Z

2

Another way to do it:

var someString = @"key1='value1' key2='value 2' key3='value3' key4='value4' key5='5555' key6='xxx666'" + " ";
Dictionary<string, string> dic = Regex.Matches(someString, @"(?<key>\w+)='(?<value>[^']*)'")
                                      .OfType<Match>()
                                      .ToDictionary(m => m.Groups["key"].Value, m => m.Groups["value"].Value);

answered Nov 2, 2014 at 14:54

Ulugbek Umirov

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1 Comment

nwsmith Over a year ago

Nice use of 'Named Matched Subexpressions' in the capture groups of the regular expression. And nice use of LINQ, with the 'Enumerable.OfType<TResult>(IEnumerable)' method.

Amit Joki · Accepted Answer · 2014-11-02 14:53:05Z

0

You can do it like this

var str = "key1='value1' key2='value 2' key3='value3' key4='value4' key5='5555' key6='xxx666'";
var arr = Regex.Split(str, "(?<=')\\s(?=\\w)"); // split on whitespace to get key=value
foreach(var s in arr) {
    var nArr = s.Split("="); // split on = to get key and value
    keyValuePairs.Add(nArr[0], nArr[1]);
}

(?<=')\s(?=\w) will look for space which is after ' and before the start of the key

edited Nov 2, 2014 at 14:53

answered Nov 2, 2014 at 14:47

Amit Joki

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