I need to insert spaces to string....

Glenn Patton

Hi All,

I need to insert some spaces to a string "12345678" needs to be "12 34 56 78" I belive there is a String format option to do the serperation but I'm having no luck finding it.

Any one any ideas.
Glenn

[Up Date]
Idea I had while typing this

MessageBox.Show(SerialNumber);

for (int i = 0; i < SerialNumber.Length; i++)

{

SerialNumberNew = SerialNumber.Insert(2," ");

}

almost worked ! almost I can get the space in the first place on the string. the space is moving down the string
MessageBox.Show(SerialNumberNew);

6 Replies

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Vulpes13y ago
Accepted answer
Yes, if the strings could be long, I'd use a StringBuilder too:

string s = "12345678";
StringBuilder sb = new StringBuilder();

for(int i = 0; i < s.Length; i += 2)
{
sb.Append(s.Substring(i, 2));
if (i < s.Length - 2) sb.Append (" ");
}

s = sb.ToString();
Console.WriteLine(s); // 12 34 56 78
Glenn Patton13y ago
Thanks Vulpes, I now have it splitting the string as I would need. My inital worries on using string builder were overcome, face your fears!!! Thanks All
Glenn
Vulpes13y ago
Just noticed the edit in your first post where you're trying to use the String.Insert method.

The reason why that doesn't work is because each time you insert a space it increases the indices of the following characters by 1. However, you can avoid that by iterating backwards through the string:

string s = "12345678";
for(int i = s.Length - 2; i >= 2; i -= 2) s = s.Insert(i, " ");
Console.WriteLine(s); // 12 34 56 78

This has the merit of brevity and, whilst it's not as efficient as StringBuilder (a lot of intermediate strings are being created), it should be fine for serial numbers.
Vulpes13y ago
I don't see how that can work, Glen, as you don't have any delimiters in the string "12345678".

However, here's another way of doing it which doesn't involve StringBuilder but requires a combination of regular expressions and LINQ:

using System.Text.RegularExpressions;
using System.Linq;

// ...

string s = "12345678";
MatchCollection mc = Regex.Matches(s, @"\d\d"); // finds each pair of 2 digits
string[] sa = (from Match m in mc select m.Value).ToArray();
s = String.Join(" ", sa);
Console.WriteLine(s); // 12 34 56 78

EDIT

Just thought of an easier way using regular expressions on their own:

string s = "12345678";
s = Regex.Replace(s, @"\d\d", "$0 ").TrimEnd();
Console.WriteLine(s); // 12 34 56 78
Glenn Patton13y ago
I have had mixed results with string build in the past. Some thing like:

string Stuff = null;

String Builder output = new StringBulider();
int ctr =2;
foreach(string subString in Stuff.split(delimeters))
{
output.AppendFormat("{0}{1}",ctr++,subString);

}
Console.WriteLine(output);

I hope!!
Glenn
Vishnujeet Kumar13y ago
you can use StringBuilder if you don't got any solution .