RegEx to match M/YYYY, MM/YYYY , M/YY or MM/YY format

Question

Need help finding or having a RegEx match a MM/YY or MM/YYYY format. My RegExFu is weak and I\'m not even sure where to begin writing this.

Months should be 1-12, y

Answer 1

Try:

var re = new Regex(@"(?\d{2})/(?\d{2}|\d{4})");
var month = re.Match(yourString).Groups["month"];
...

An alternative is:

if(dateStr.Length == 5)
    myDateTime = DateTime.ParseExact("MM/YY", dateStr);
else
    myDateTime = DateTime.ParseExact("MM/YYYY", dateStr);