How to use RegEx?

Question

Hi,

I haven't used RegEx so please excuse me...

I have a string like:

string str = "https://abce/MyTest";

I want to check if the particular string starts with "https://" and ends with "/MyTest".

How can I acheive that?

Answer 1

This regular expression:

^https://.*/MyTest$

will do what you ask.

^ matches the beginning of the string.

https:// will match exactly that.

.* will match any number of characters (the * part) of any kind (the . part). If you want to make sure there is at least one character in the middle, use .+ instead.

/MyTest matches exactly that.

$ matches the end of the string.

To verify the match, use:

Regex.IsMatch(str, @"^https://.*/MyTest$");

More info at the MSDN Regex page.

Answer 2

Try the following:

var str = "https://abce/MyTest";
var match = Regex.IsMatch(str, "^https://.+/MyTest$");

The ^ identifier matches the start of the string, while the $ identifier matches the end of the string. The .+ bit simply means any sequence of chars (except a null sequence).

You need to import the System.Text.RegularExpressions namespace for this, of course.

Answer 3

In .NET:

^https://.*/MyTest$

Answer 4

HAndy tool for genrating regular expressions

http://txt2re.com/

Answer 5

Try Expresso, good for building .NET regexes and teaching you the syntax at the same time.

Answer 6

I want to check if the particular string starts with "https://" and ends with "/MyTest".

Well, you could use regex for that. But it's clearer (and probably quicker) to just say what you mean:

str.StartsWith("https://") && str.EndsWith("/MyTest")

You then don't have to worry about whether any of the characters in your match strings need escaping in regex. (For this example, they don't.)