Regular Expression to get all characters before -

Question

How can I get the string before the character  -  using regular expressions   For example  I have  text-1  and I want to return  text

User · Accepted Answer

So I see many possibilities to achieve this.

string text = "Foobar-test";

Regex Match everything till the first "-"
```
Match result = Regex.Match(text, @"^.*?(?=-)");
```
- ^ match from the start of the string
- .*? match any character (.), zero or more times (*) but as less as possible (?)
- (?=-) till the next character is a "-" (this is a positive look ahead)
Regex Match anything that is not a "-" from the start of the string
```
Match result2 = Regex.Match(text, @"^[^-]*");
```
- [^-]* matches any character that is not a "-" zero or more times
Regex Match anything that is not a "-" from the start of the string till a "-"
```
Match result21 = Regex.Match(text, @"^([^-]*)-");
```
Will only match if there is a dash in the string, but the result is then found in capture group 1.
Split on "-"
```
string[] result3 = text.Split('-');
```
Result is an Array the part before the first "-" is the first item in the Array
Substring till the first "-"
```
string result4 = text.Substring(0, text.IndexOf("-"));
```
Get the substring from text from the start till the first occurrence of "-" (text.IndexOf("-"))

You get then all the results (all the same) with this

Console.WriteLine(result);
Console.WriteLine(result2);
Console.WriteLine(result21.Groups[1]);
Console.WriteLine(result3[0]);
Console.WriteLine(result4);

I would prefer the first method.

You need to think also about the behavior, when there is no dash in the string. The fourth method will throw an exception in that case, because text.IndexOf("-") will be -1. Method 1 and 2.1 will return nothing and method 2 and 3 will return the complete string.

User · Answer

I dont think you need regex to achieve this  I would look at the SubString method along with the indexOf method  If you need more help  add a comment showing what you have attempted and I will offer more help

User · Answer

You could just use another non-regex based method  Someone gave the suggestion of using Substring  but you could also use Split   string testString    my-string   string   splitString   testString Split  -    string resultingString   splitString 0     my   See http   msdn microsoft com en-US library ms228388 28v VS 80 29 aspx for another good example

User · Answer

If you want use RegEx in  NET   Regex rx   new Regex       w     -      var match   rx Match  thisis-thefirst    var text   match Groups 1  Value  Assert AreEqual  thisis   text

User · Answer

Find all word and space characters up to and including a -     w   -

User · Answer

Here is my suggestion - it s quite simple as that     -

User · Answer

This is something like the regular expression you need      -   -   Quick tests in JavaScript       -   -  exec  text-1   1      text       -   -  exec  foo-bar-1   1      foo       -   -  exec  -1   1             -   -  exec  quux   1     explodes

[c#] Regular Expression to get all characters before "-"

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