How to split string after every n-th character?

Question

I have a string and I want to split the string after every 2nd comma. Is this doable using split string in c#?

Example string:

"This,is,an, example,for,the,stackoverflow,community"

Desired output

This,is
an,example
for,the
stackoverflow,community

Any help would be much appreciated thanks!

No, you can either to this with a regex or a manually written loop. Split works on every instance of the character. — Zdeněk Jelínek, Mar 06 '22 at 20:50
Did you mean: "This is, an example, for the, stackoverflow community" ? Because what you have is not every 2nd comma — beautifulcoder, Mar 06 '22 at 20:50
@Heinzi They don't show an actual attempt to solve it themselves, thus likely down voted for lack of research. — juharr, Mar 06 '22 at 21:14

Heinzi · Answer 1 · 2022-03-06T21:08:56.877

5

Using Enumerable.Chunk from .NET 6, you can

split on ",",
create chunks of two items each and
re-join those chunks:

string input = "This,is,an,example,for,the,stackoverflow,community";

var output = input.Split(",")
    .Chunk(2)
    .Select(chunk => string.Join(",", chunk));

foreach (string s in output)
    Console.WriteLine(s);

fiddle

If you're stuck with the "classic" .NET Framework, here are chunk implementations for .NET < 6:

how do I chunk an enumerable?

edited Mar 06 '22 at 21:08

answered Mar 06 '22 at 21:01

Heinzi

167,459
57
363
519

Ow, nice. I didn't know of `Chuck`. – Stefan Mar 06 '22 at 21:08
`Split(",")` will not work as there is no overload that only takes a string. Instead use `Split(',')` – juharr Mar 06 '22 at 21:16
@juharr In .net 6 it will work. – Hamlet Hakobyan Mar 06 '22 at 21:19
@HamletHakobyan Oh they made the StringSplitOptions optional. – juharr Mar 06 '22 at 22:06
Thanks for the replies! This solution works perfectly but unfortunately im running on .net core 3.1 so chunk wouldn’t work for me :/ chunk enumerable seems pretty complex for a split string. Would regex.split work ? I have tried to get the combination but was unsuccessful – Shafeel Mohammed Mar 06 '22 at 22:35

Axel Kemper · Answer 2 · 2022-03-06T21:49:16.423

2

You could do something like this:

var s = "This,is,an, example,for, the, stackoverflow, community";

var a = ("," + s + ",").Split(',');

//  requires using System.Linq;
var b = Enumerable.Range(0, a.Length / 2)
        .Select(i => $"{a[2 * i]}, {a[2 * i + 1]}".Trim(',', ' '));

Range enumerates the resulting array and computes concatenations of the corresponding pairs of strings.

edited Mar 06 '22 at 21:49

answered Mar 06 '22 at 20:54

Axel Kemper

10,544
2
31
54

1

Maybe you want `var c = string.Join("\r\n", b);` in the end, or similar. – Jeppe Stig Nielsen Mar 06 '22 at 20:59
Agree with @JeppeStigNielsen: the output seems still wrong. I like the two-liner though. – Stefan Mar 06 '22 at 21:04
2

See this fiddle: https://dotnetfiddle.net/yqkw53 – Stefan Mar 06 '22 at 21:06

score 0 · Answer 3 · answered Mar 07 '22 at 11:18

You could also use a pattern to match 1 or more characters except for a comma using a negated character class [^,]+ before and after the comma:

string pattern = @"[^,]+,[^,]+";
string input = "This,is,an, example,for,the,stackoverflow,community";
foreach (Match m in Regex.Matches(input, pattern))
{
    Console.WriteLine(m.Value);
}

Output

This,is
an, example
for,the
stackoverflow,community

How to split string after every n-th character?

3 Answers3