C# split string by multiple characters

Question

I want to split a string like this:

"---hello--- hello ------- hello --- bye"

into an array like this:

"hello" ; "hello ------- hello" ; "bye"

I tried it with this command:

test.Split(new string[] {"---"}, StringSplitOptions.RemoveEmptyEntries);

But that doesn't work, it splits the "-------" into 3 this "---- hello".

Edit:

I can't modify the text, it is an input and I don't know how it looks like before I have to modify it.

An other example would be:

--- example ---

--------- example text --------

--- example 2 ---

and it should only split the ones with 3 hyphens not the one with more.

@RegisPortalez yea but thats the problem, I want to split it exactly like this, even if it contains it. — Hans Dabi
– Hans Dabi, Commented Apr 4, 2017 at 12:17
the String.Split is not the correct choice here. It cannnot do what you want. I think regex will be your friend — swe
– swe, Commented Apr 4, 2017 at 12:19
Do you have few other examples? Someone can propose you solution which will work only on given example. It's hard to provide robust solution when we don't know which parts of your string could change. — Darjan Bogdan
– Darjan Bogdan, Commented Apr 4, 2017 at 12:19
@swe do you have a solution with regex? I'm really bad at it. — Hans Dabi
– Hans Dabi, Commented Apr 4, 2017 at 12:21

Community · Accepted Answer · 2017-05-23 11:54:25Z

6

You can use a Regex split. The regex uses a negative lookahead (?!-) to only match three - exactly. See also Get exact match of the word using Regex in C#.

string sentence = "---hello--- hello ------- hello --- bye";
var result = Regex.Split(sentence, @"(?<!-)---(?!-)");
foreach (string value in result) {
   Console.WriteLine(value.Trim());
}

.net Fiddle

edited May 23, 2017 at 11:54

CommunityBot

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answered Apr 4, 2017 at 12:31

Georg Patscheider

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1 Comment

swe Over a year ago

same answer, same time :)

swe · Accepted Answer · 2017-04-04 12:32:03Z

4

Solution to find your Tokens with regex:

(?<!-)---(?!-)

Console.WriteLine(String.Join(",", System.Text.RegularExpressions.Regex.Split("---hello--- hello ------- hello --- bye", "(?<!-)---(?!-)")))

answered Apr 4, 2017 at 12:32

swe

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Comments

Dmitrii Bychenko · Accepted Answer · 2017-04-04 12:29:30Z

3

I suggest trying Regex.Split instead of string.Split:

  string source = "---hello1--- hello2 ------- hello3 --- bye";

  var result = Regex
    .Split(source, @"(?<=[^-]|^)-{3}(?=[^-]|$)") // splitter is three "-" only
    .Where(item => !string.IsNullOrEmpty(item))  // Removing Empty Entries
    .ToArray();

  Console.Write(string.Join(";", result));

Outcome:

  hello1; hello2 ------- hello3 ; bye

answered Apr 4, 2017 at 12:29

Dmitrii Bychenko

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1 Comment

Hans Dabi Over a year ago

That was exactly what I was looking for, thank you :)

Bestter · Accepted Answer · 2017-04-04 12:19:09Z

2

Replace ----- by something else that is never is your test, like @@@ test.replace("------", "@@@")
Split your string
Replace @@@ by ------

answered Apr 4, 2017 at 12:19

Bestter

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2 Comments

DavidG Over a year ago

What about sequences of 4, 6, 7, 8 etc?

Hans Dabi Over a year ago

The problem is I don't know how much chars the string contains, the input can be different every time, so that solution doesn't work for me.

Milan Blažek · Accepted Answer · 2017-04-04 12:26:08Z

0

I would suggest using an neutral character like "/split" or something like that. Than you can use test.Split(...) without woriing that it split something else that you want. Your code would now look something like that:

string test = "hello\split hello ------- hello \split bye";
test.Split("\split", StringSplitOptions.RemoveEmptyEntries);

answered Apr 4, 2017 at 12:26

Milan Blažek

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2 Comments

DavidG Over a year ago

You are assuming that OP has the choice to change the input, which I very much doubt here.

Hans Dabi Over a year ago

@DavidG exactly, I can't do that.

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