Splitting string into an array on 16th char

Question

I have a text file with various 16 char strings both appended to one another and on separate lines. I've done this

FileInfo f = new FileInfo("d:\\test.txt");
string FilePath = ("d:\\test.txt");
string FileText = new System.IO.StreamReader(FilePath).ReadToEnd().Replace("\r\n", "");
CharCount = FileText.Length;

To remove all of the new lines and create one massively appended string. I need now to split this massive string into an array. I need to split it up on the consecutive 16th char until the end. Can anyone guide me in the right direction? I've taken a look at various methods in String such as Split and in StreamReader but am confused as to what the best way to go about it would be. I'm sure it's simple but I can't figure it out.

Thank you.

So you simply want to remove the newline characters? – Rob Apr 21 '14 at 09:24 — Rob, Apr 21 '14 at 09:24
@Herblore so each line in the file has 16 chars? – dkozl Apr 21 '14 at 09:29 — dkozl, Apr 21 '14 at 09:29

Danvil · Answer 1 · 2014-04-21T11:28:59.820

0

Create a list to hold your tokens. Then get subsequent substrings of length 16 and add them to the list.

List<string> tokens = new List<string>();
for(int i=0; i+16<=FileText.Length; i+=16) {
    tokens.Add(FileText.Substring(i,16));
}

As mentioned in the comments, this ignores the last token if it has less than 16 characters. If you want it anyway you can write:

List<string> tokens = new List<string>();
for(int i=0; i<FileText.Length; i+=16) {
    int len = Math.Min(16, FileText.Length-i));
    tokens.Add(FileText.Substring(i,len);
}

edited Apr 21 '14 at 11:28

answered Apr 21 '14 at 09:25

Danvil

22,240
19
65
88

2

Will fail if string length is not multiple of 16. – Ulugbek Umirov Apr 21 '14 at 09:31
@UlugbekUmirov: Thanks for spotting. It should work now. – Danvil Apr 21 '14 at 09:32
I think we shouldn't ignore last part if it has length less than 16. You could use `Math.Min(16, FileText.Length - i)` as length argument. – Ulugbek Umirov Apr 21 '14 at 09:34

score 0 · Answer 2 · edited May 23 '17 at 10:26

Adapting the answer from here:

You could try something like so:

        string longstr = "thisisaverylongstringveryveryveryveryverythisisaverylongstringveryveryveryveryvery";
        IEnumerable<string> splitString = Regex.Split(longstr, "(.{16})").Where(s => s != String.Empty);
        foreach (string str in splitString)
        {
            System.Console.WriteLine(str);
        }

Yields:

thisisaverylongs    
tringveryveryver    
yveryverythisisa    
verylongstringve    
ryveryveryveryve
ry

keenthinker · Answer 3 · 2014-04-21T10:25:30.380

One possible solution could look like this (extracted as extension method and made dynamic, in case different token size is needed and no hard-coded dependencies):

public static class ProjectExtensions
{
    public static String[] Chunkify(this String input, int chunkSize = 16)
    {
        // result
        var output = new List<String>();
        // temp helper
        var chunk = String.Empty;
        long counter = 0;
        // tokenize to 16 chars
        input.ToCharArray().ToList().ForEach(ch => 
        {
            counter++;
            chunk += ch;
            if ((counter % chunkSize) == 0)
            {
                output.Add(chunk);
                chunk = String.Empty;
            }
        });
        // add the rest
        output.Add(chunk);

        return output.ToArray();
    }
}

The standard usage (16 chars) looks like this:

// 3 inputs x 16 characters and 1 x 10 characters
var input = @"1234567890ABCDEF1234567890ABCDEF1234567890ABCDEF1234567890";
foreach (var chunk in input.Chunkify())
{
    Console.WriteLine(chunk);
}

The output is:

1234567890ABCDEF
1234567890ABCDEF
1234567890ABCDEF
1234567890

Usage with different token size:

foreach (var chunk in input.Chunkify(13))
{
    Console.WriteLine(chunk);
}

and the corresponding output:

1234567890ABC
DEF1234567890
ABCDEF1234567
890ABCDEF1234
567890

It is not a fancy solution (and could propably be optimised for speed), but it works and it is easy to understand and implement.

Poomrokc The 3years · Answer 4 · 2014-04-21T10:01:08.497

-1

Please try this method. I haven't tried it , but used it once.

    int CharCount = FileText.Length;
    int arrayhold = (CharCount/16)+2;
    int count=0;
    string[] array = new string[arrayhold];
    for(int i=0; i<FileText.Length; i+=16)
       {
          int currentleft = FileText.Length-(16*count);
          if(currentleft>16)
            {
                  array[count]=FileText.Substring(i,16);
            }
          if(currentleft<16)
            {
                  array[count]=FileText.Substring(i,currentleft);
            }

              count++;
        }

This is the new code and provide a TRUE leftovers handling. Tested in ideone

Hope it works

edited Apr 21 '14 at 10:01

answered Apr 21 '14 at 09:31

Poomrokc The 3years

1,099
2
10
23

-1 Reason is [here](http://ideone.com/dlEwAD) What about remaining characters? – Sriram Sakthivel Apr 21 '14 at 09:38
@SriramSakthivel Now it works , proved by [this](http://ideone.com/2gzE7Q) adding proper way to handle the leftovers. And thanks for ideone. – Poomrokc The 3years Apr 21 '14 at 10:02
@All downvoters , please see this and fix the downvotes , now it works! :( Preferably , upvotes Xb – Poomrokc The 3years Apr 21 '14 at 10:04

Yuval Itzchakov · Answer 5 · 2014-04-21T10:22:45.003

-1

Try this one:

var testArray = "sdfsdfjshdfalkjsdfhalsdkfjhalsdkfjhasldkjfhasldkfjhasdflkjhasdlfkjhasdlfkjhasdlfkjhasldfkjhalsjfdkhklahjsf";
var i = 0;
var query = from s in testArray
            let num = i++
            group s by num / 16 into g
            select new {Value = new string(g.ToArray())};

var result = query.Select(x => x.Value).ToList();

result is List containing all the 16 char strings.

edited Apr 21 '14 at 10:22

answered Apr 21 '14 at 10:13

Yuval Itzchakov

146,575
32
257
321

Why the -1? whats wrong with the answer? – Yuval Itzchakov Apr 21 '14 at 13:22

Splitting string into an array on 16th char

5 Answers5