Transform string by regular expression

Question

Is there a way to transform string like

http://blar1.s3.shamazonaws.com/ZZ/bstd-20140801-004000-0500.time.gz

to

C:\Temp\2014\08\

using single regular expression?

There a lot of files to download regulary, and I need to store these files in a directorty structure organized by year and month. They all have same date part in name - like "20140801-004000-0500" in my example here, but other parts of link can differ.

Answer 1

You can use this regex:

^                 # start of the string
.+-               # match everything until the first hyphen
(?<year>\d{4})    # capture the first four digits into a group named year
(?<month>\d{2})   # capture the next two digits into a group named month
(?<day>\d{2})     # you get the idea...
-.+$              # match everything else until the end of the string

The following snipped should do the work:

string strRegex = @"^.+-(?<year>\d{4})(?<month>\d{2})(?<day>\d{2})-.+$";
Regex myRegex = new Regex(strRegex, RegexOptions.None);
string strTargetString = @"http://blar1.s3.shamazonaws.com/ZZ/bstd-20140801-004000-0500.time.gz";
string strReplace = @"C:\Temp\${year}\${month}";

return myRegex.Replace(strTargetString, strReplace);