通用字符串拆分难题/字符串C＃中的时间

Question

This question is more an open ended what is best practice, or what do you do think is good practice scenario ? I'm trying to get two times, separate out their numbers so they can be placed into a DateTime value.

Example which I think is the quickest and cleanest but I am not sure...

string a = "11:50-12:30";
a = Regex.Replace(a, @"[^\d]", ""); //output 11501230
string time_1 = a.Substring(0, 3);
string time_2 = a.Substring(4, 7);
// DO SOME parsing of strings to ints
DateTime Start = new DateTime(DateTime.Today.Year, DateTime.Today.Month, DateTime.Today.Day, //enter some separate ints here)

But perhaps I can do something like ? and this can't be signifcantly slower can it ? perhaps its quicker?

string a = "11:50-12:30"
string a_1 = a.substring(0,4);
string b = DateTime.Today.Year.toString() + DateTime.Today.Month.toString() + DateTime.Today.Day.toString() + "11:50-12:30";
DateTime mytime = DateTime.ParseExact(a_1, "yyyy-MM-dd HH:mm", CultureInfo.InvariantCulture);

Answer 1

Nothing to do with efficiency but: As you are primarily concerned with times why not parse each part to a System.TimeSpan and that could then be added to a DateTime instance (using Add ) if you want it to represent a moment in time.

string a = "11:50-12:30";
var parts = a.Split('-');
var time_1 = TimeSpan.Parse(parts[0]);
var time_2 = TimeSpan.Parse(parts[1]);
var start = DateTime.Today.Add(time_1);
var end = DateTime.Today.Add(time_2);

I omitted error checking on the Split call to check that there are 2 parts and also on Parse which would be advisable. You could also use TryParse but you get the idea.

Answer 2

You can test performance manually using Stopwatch from System.Diagnostics

    string a = "11:50-12:30";

    Stopwatch watch = new Stopwatch();
    watch.Start();
    DateTime start = DateTime.Today.Add(DateTime.ParseExact(a.Split('-').First(), "hh:mm", CultureInfo.InvariantCulture).TimeOfDay);
    DateTime end = DateTime.Today.Add(DateTime.ParseExact(a.Split('-').Last(), "hh:mm", CultureInfo.InvariantCulture).TimeOfDay);
    watch.Stop();
    Console.WriteLine(watch.Elapsed.ToString());
    Console.WriteLine(start.ToString());
    Console.WriteLine(end.ToString());