I have a string like s = "abcdefgh". I want to split it by number of characters like:
a(0)="ab"
a(1)="cd"
a(2)="ef"
a(3)="gh"
Can someone tell me how to do this?
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What is your criteria for splitting? Every time the character changes? Every second character?mellamokb– mellamokb2012-07-26 18:27:52 +00:00Commented Jul 26, 2012 at 18:27
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3Example isn't clear. Do you want to split per 2 chars or split whenever the next char isn't identical to the previous one?Eddy– Eddy2012-07-26 18:27:53 +00:00Commented Jul 26, 2012 at 18:27
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1How would you split "abbcdccceeee", for example? (Your question doesn't say much about what you're trying to do...)lc.– lc.2012-07-26 18:28:00 +00:00Commented Jul 26, 2012 at 18:28
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4 Answers
You can use a regular expression to split into two-character groups:
Dim parts = Regex.Matches(s, ".{2}").Cast(Of Match)().Select(Function(m) m.Value)
Demo: http://ideone.com/ZVL2a (C#)
3 Comments
Konrad Rudolph
The
[…] around the Select is unnecessary. Otherwise, this is how I’d do it as well. Just pay attention that . doesn’t match every character unless you specify the SingleLine flag.
mellamokb
@KonradRudolph: Thanks. I wrote it in C# first and used an online converter. I'm not very good with VB.Net :) Strangely enough, when I tried to do a VB.Net sample, I got internal errors and a note about
System.Linq not being a valid library: ideone.com/KlCAu. Did I do something wrong?Konrad Rudolph
The VB.NET compiler for Mono is unfortunately a lost cause. It is completely unusable. I find that a pity since I originally come from VB but I don’t foresee the situation changing soon so you are essentially forced to use C# if you want to write for non-Windows platforms. That said, your VB code on ideone contains a small error, the
part as var is wrong, it should just be For Each part, or alternatively … part As Match (and then the Cast would be unnecessary). But that won’t fix the internal compiler error.Here's a Linq method that doesn't require writing a loop:
Const splitLength As Integer = 2
Dim a = Enumerable.Range(0, s.Length \ splitLength).
Select(Function(i) s.Substring(i * splitLength, splitLength))
3 Comments
lc.
+1 I was in the middle of writing the exact same thing. Do realize this will blow up on odd-length strings (as most of the other answers as well)
Antagony
@lc Are you sure? I tested it on 2, 3, 4, 5 & 6 and it always seemed to work okay. The only problem I found was if the original string's length wasn't an exact multiple of the split length – in which case the last few characters were omitted.
lc.
Actually you're right, it won't blow up (I was thinking of using a ceiling function to get the last bit). It will however omit the last short bit as you say.
Splitting every 2 chars, is what I think you wanted
Dim s As String = "aabbccdd"
For i As Integer = 0 To s.Length - 1 Step 1
If i Mod 2 = 0 Then
Console.WriteLine(s.Substring(i, 2))
End If
Next
2 Comments
Konrad Rudolph
Why don’t you simply increment in steps of 2 instead of using the additional check?
Orn Kristjansson
Yea that would be even better
I you would use a List(Of String) instead, it simplifies it:
Dim s = "aabbccdde" ' yes, it works also with an odd number of chars '
Dim len = 2
Dim list = New List(Of String)
For i = 0 To s.Length - 1 Step len
Dim part = If(i + len > s.Length, s.Substring(i), s.Substring(i, len))
list.Add(part)
Next
Dim result = list.ToArray() ' if you really need that array '
