HOWTO - generate a alphanumeric string of a given length

[Crirus]

Is there a function that return some random ID like string alphanumeric?
Like this:
A35sDsd1dSGsH

Thanks
Crirus

[One Handed Man]

Try this - OHM

Public Class StringGenerator

Public Shared Function RandomString(le ngth As Integer) As String
Const zero As Integer = CInt("0"c)
Const nine As Integer = CInt("9"c)
Const capA As Integer = CInt("A"c)
Const capZ As Integer = CInt("Z"c)

Dim guid As Byte() = Guid.NewGuid(). ToByteArray()
Dim seed As Integer = guid(0) + Machine.Shift.L eft(guid(1), 8) +
Machine.Shift.L eft(guid(2), 16) + Machine.Shift.L eft(guid(3), 24)

Dim r As New Random(seed)

Dim s As String = Nothing
Dim i As Integer
For i = 0 To length - 1
Dim n As Integer
Do
n = r.Next(zero, capZ)
Loop While Not(n >= zero And n <= nine Or(n >= capA And n <= capZ))
s += CChar(n)
Next i

Return s
End Function 'RandomString
End Class 'StringGenerato r


Crirus wrote:

Is there a function that return some random ID like string
alphanumeric? Like this:
A35sDsd1dSGsH

Thanks
Crirus

[Cor]

HI OHM,

Not only random but with build in Ohandedcator.

:-))

Cor

[Tom Shelton]

In article <#5************ **@TK2MSFTNGP10 .phx.gbl>, Crirus wrote:

Is there a function that return some random ID like string alphanumeric?
Like this:
A35sDsd1dSGsH

Thanks
Crirus

How long do you want it?

Dim id As String = Guid.NewGuid(). ToString().Repl ace("-", String.Empty)
Console.WriteLi ne(id)

That will produce a 32 character string of hex digits (0-9 and a-f),
that is statistically unique (basically, it is pretty much guarented
that it will never be duplicated).

--
Tom Shelton
MVP [Visual Basic]

[One Handed Man]

LOL

Cor wrote:

HI OHM,

Not only random but with build in Ohandedcator.

:-))

Cor

[Mick Doherty]

What's that CInt("0"c)? doesn't work here although Asc("0"c) does, as does
Asc("0").
What's that Machine.Shift.L eft? doesn't work here. I understand what it's
meant to do though.(number between 0 and &HFFFFFFFF).
I like that Random class, hadn't seen that before, but, according to the
documentation, for best performance Random should only be created once.
StringBuilder.A ppend is faster than String +=.
You missed the LCase characters.

My much simpler version of that same function, with default time based
seeding of Random:

Private r As New Random
'I think 255 characters should be enough, although there's no reason that
'you can't use Integer or Short instead of Byte, and have more.
Private Function RandomString(By Val Stringlength As Byte) As String

Dim s As String = _
"0123456789ABCD EFGHIJKLMNOPQRS TUVWXYZabcdefgh ijklmnopqrstuvw xyz"
Dim sb As New System.Text.Str ingBuilder

Do
sb.Append(s.Cha rs(r.Next(0, 61)))
Loop While sb.Length < Stringlength

Return sb.ToString

End Function

My version generated 100000 * 255character strings in 4 secs as opposed to
yours (updated to use stringbuilder and default seeding for comparison)
taking 6 secs(making the Random object a Class level Private object reduced
this to 5 secs). Without Stringbuilder yours took 23 secs and 21 secs.

Before that Random Class I used the old Rnd function and the fastest I could
get, even using Stringbuilder, was 28 secs.

So I learned something useful Today.
Thankyou

Mick Doherty

"One Handed Man" <Bo****@Duck.ne t> wrote in message
news:bo******** **@titan.btinte rnet.com...

Try this - OHM

Public Class StringGenerator

Public Shared Function RandomString(le ngth As Integer) As String
Const zero As Integer = CInt("0"c)
Const nine As Integer = CInt("9"c)
Const capA As Integer = CInt("A"c)
Const capZ As Integer = CInt("Z"c)

Dim guid As Byte() = Guid.NewGuid(). ToByteArray()
Dim seed As Integer = guid(0) + Machine.Shift.L eft(guid(1), 8) +
Machine.Shift.L eft(guid(2), 16) + Machine.Shift.L eft(guid(3), 24)

Dim r As New Random(seed)

Dim s As String = Nothing
Dim i As Integer
For i = 0 To length - 1
Dim n As Integer
Do
n = r.Next(zero, capZ)
Loop While Not(n >= zero And n <= nine Or(n >= capA And n <= capZ)) s += CChar(n)
Next i

Return s
End Function 'RandomString
End Class 'StringGenerato r


Crirus wrote:

Is there a function that return some random ID like string
alphanumeric? Like this:
A35sDsd1dSGsH

Thanks
Crirus

[One Handed Man]

What version of .NET framework are you using


Mick Doherty wrote:

What's that CInt("0"c)? doesn't work here although Asc("0"c) does, as
does Asc("0").
What's that Machine.Shift.L eft? doesn't work here. I understand what
it's meant to do though.(number between 0 and &HFFFFFFFF).
I like that Random class, hadn't seen that before, but, according to
the documentation, for best performance Random should only be created
once. StringBuilder.A ppend is faster than String +=.
You missed the LCase characters.

My much simpler version of that same function, with default time based
seeding of Random:

Private r As New Random
'I think 255 characters should be enough, although there's no reason
that 'you can't use Integer or Short instead of Byte, and have more.
Private Function RandomString(By Val Stringlength As Byte) As String

Dim s As String = _
"0123456789ABCD EFGHIJKLMNOPQRS TUVWXYZabcdefgh ijklmnopqrstuvw xyz"
Dim sb As New System.Text.Str ingBuilder

Do
sb.Append(s.Cha rs(r.Next(0, 61)))
Loop While sb.Length < Stringlength

Return sb.ToString

End Function

My version generated 100000 * 255character strings in 4 secs as
opposed to yours (updated to use stringbuilder and default seeding
for comparison) taking 6 secs(making the Random object a Class level
Private object reduced this to 5 secs). Without Stringbuilder yours
took 23 secs and 21 secs.

Before that Random Class I used the old Rnd function and the fastest
I could get, even using Stringbuilder, was 28 secs.

So I learned something useful Today.
Thankyou

Mick Doherty

"One Handed Man" <Bo****@Duck.ne t> wrote in message
news:bo******** **@titan.btinte rnet.com...

Try this - OHM

Public Class StringGenerator

Public Shared Function RandomString(le ngth As Integer) As String
Const zero As Integer = CInt("0"c)
Const nine As Integer = CInt("9"c)
Const capA As Integer = CInt("A"c)
Const capZ As Integer = CInt("Z"c)

Dim guid As Byte() = Guid.NewGuid(). ToByteArray()
Dim seed As Integer = guid(0) + Machine.Shift.L eft(guid(1), 8)
+ Machine.Shift.L eft(guid(2), 16) + Machine.Shift.L eft(guid(3), 24)

Dim r As New Random(seed)

Dim s As String = Nothing
Dim i As Integer
For i = 0 To length - 1
Dim n As Integer
Do
n = r.Next(zero, capZ)
Loop While Not(n >= zero And n <= nine Or(n >= capA And n
<= capZ)) s += CChar(n)
Next i

Return s
End Function 'RandomString
End Class 'StringGenerato r


Crirus wrote:

Is there a function that return some random ID like string
alphanumeric? Like this:
A35sDsd1dSGsH

Thanks
Crirus

[Mick Doherty]

1.1.4322.573 (VS2003)

"One Handed Man" <Bo****@Duck.ne t> wrote in message
news:bo******** **@titan.btinte rnet.com...

What version of .NET framework are you using


Mick Doherty wrote:

What's that CInt("0"c)? doesn't work here although Asc("0"c) does, as
does Asc("0").
What's that Machine.Shift.L eft? doesn't work here. I understand what
it's meant to do though.(number between 0 and &HFFFFFFFF).
I like that Random class, hadn't seen that before, but, according to
the documentation, for best performance Random should only be created
once. StringBuilder.A ppend is faster than String +=.
You missed the LCase characters.

My much simpler version of that same function, with default time based
seeding of Random:

Private r As New Random
'I think 255 characters should be enough, although there's no reason
that 'you can't use Integer or Short instead of Byte, and have more.
Private Function RandomString(By Val Stringlength As Byte) As String

Dim s As String = _
"0123456789ABCD EFGHIJKLMNOPQRS TUVWXYZabcdefgh ijklmnopqrstuvw xyz"
Dim sb As New System.Text.Str ingBuilder

Do
sb.Append(s.Cha rs(r.Next(0, 61)))
Loop While sb.Length < Stringlength

Return sb.ToString

End Function

My version generated 100000 * 255character strings in 4 secs as
opposed to yours (updated to use stringbuilder and default seeding
for comparison) taking 6 secs(making the Random object a Class level
Private object reduced this to 5 secs). Without Stringbuilder yours
took 23 secs and 21 secs.

Before that Random Class I used the old Rnd function and the fastest
I could get, even using Stringbuilder, was 28 secs.

So I learned something useful Today.
Thankyou

Mick Doherty

"One Handed Man" <Bo****@Duck.ne t> wrote in message
news:bo******** **@titan.btinte rnet.com...

Try this - OHM

Public Class StringGenerator

Public Shared Function RandomString(le ngth As Integer) As String
Const zero As Integer = CInt("0"c)
Const nine As Integer = CInt("9"c)
Const capA As Integer = CInt("A"c)
Const capZ As Integer = CInt("Z"c)

Dim guid As Byte() = Guid.NewGuid(). ToByteArray()
Dim seed As Integer = guid(0) + Machine.Shift.L eft(guid(1), 8)
+ Machine.Shift.L eft(guid(2), 16) + Machine.Shift.L eft(guid(3), 24)

Dim r As New Random(seed)

Dim s As String = Nothing
Dim i As Integer
For i = 0 To length - 1
Dim n As Integer
Do
n = r.Next(zero, capZ)
Loop While Not(n >= zero And n <= nine Or(n >= capA And n
<= capZ)) s += CChar(n)
Next i

Return s
End Function 'RandomString
End Class 'StringGenerato r


Crirus wrote:
Is there a function that return some random ID like string
alphanumeric? Like this:
A35sDsd1dSGsH

Thanks
Crirus

[One Handed Man]

Actually, this was converted from C# ( from an earlier version ) , so I
hadnt tested it in VB.NET.

Never mind the basic phlisophy was there.

OHM

Mick Doherty wrote:

1.1.4322.573 (VS2003)

"One Handed Man" <Bo****@Duck.ne t> wrote in message
news:bo******** **@titan.btinte rnet.com...

What version of .NET framework are you using


Mick Doherty wrote:

What's that CInt("0"c)? doesn't work here although Asc("0"c) does,
as does Asc("0").
What's that Machine.Shift.L eft? doesn't work here. I understand what
it's meant to do though.(number between 0 and &HFFFFFFFF).
I like that Random class, hadn't seen that before, but, according to
the documentation, for best performance Random should only be
created once. StringBuilder.A ppend is faster than String +=.
You missed the LCase characters.

My much simpler version of that same function, with default time
based seeding of Random:

Private r As New Random
'I think 255 characters should be enough, although there's no reason
that 'you can't use Integer or Short instead of Byte, and have more.
Private Function RandomString(By Val Stringlength As Byte) As String

Dim s As String = _
"0123456789ABCD EFGHIJKLMNOPQRS TUVWXYZabcdefgh ijklmnopqrstuvw xyz"
Dim sb As New System.Text.Str ingBuilder

Do
sb.Append(s.Cha rs(r.Next(0, 61)))
Loop While sb.Length < Stringlength

Return sb.ToString

End Function

My version generated 100000 * 255character strings in 4 secs as
opposed to yours (updated to use stringbuilder and default seeding
for comparison) taking 6 secs(making the Random object a Class
level Private object reduced this to 5 secs). Without Stringbuilder
yours took 23 secs and 21 secs.

Before that Random Class I used the old Rnd function and the fastest
I could get, even using Stringbuilder, was 28 secs.

So I learned something useful Today.
Thankyou

Mick Doherty

"One Handed Man" <Bo****@Duck.ne t> wrote in message
news:bo******** **@titan.btinte rnet.com...
Try this - OHM

Public Class StringGenerator

Public Shared Function RandomString(le ngth As Integer) As String
Const zero As Integer = CInt("0"c)
Const nine As Integer = CInt("9"c)
Const capA As Integer = CInt("A"c)
Const capZ As Integer = CInt("Z"c)

Dim guid As Byte() = Guid.NewGuid(). ToByteArray()
Dim seed As Integer = guid(0) + Machine.Shift.L eft(guid(1),
8) + Machine.Shift.L eft(guid(2), 16) + Machine.Shift.L eft(guid(3),
24)

Dim r As New Random(seed)

Dim s As String = Nothing
Dim i As Integer
For i = 0 To length - 1
Dim n As Integer
Do
n = r.Next(zero, capZ)
Loop While Not(n >= zero And n <= nine Or(n >= capA And n
<= capZ)) s += CChar(n)
Next i

Return s
End Function 'RandomString
End Class 'StringGenerato r


Crirus wrote:
> Is there a function that return some random ID like string
> alphanumeric? Like this:
> A35sDsd1dSGsH
>
> Thanks
> Crirus

[Crirus]

So Random class is much better than rnd function?

--
Ceers,
Crirus

------------------------------
If work were a good thing, the boss would take it all from you

------------------------------

"Mick Doherty" <md*******@nosp am.ntlworld.com > wrote in message
news:Qa******** *********@newsf ep1-win.server.ntli .net...

What's that CInt("0"c)? doesn't work here although Asc("0"c) does, as does
Asc("0").
What's that Machine.Shift.L eft? doesn't work here. I understand what it's
meant to do though.(number between 0 and &HFFFFFFFF).
I like that Random class, hadn't seen that before, but, according to the
documentation, for best performance Random should only be created once.
StringBuilder.A ppend is faster than String +=.
You missed the LCase characters.

My much simpler version of that same function, with default time based
seeding of Random:

Private r As New Random
'I think 255 characters should be enough, although there's no reason that
'you can't use Integer or Short instead of Byte, and have more.
Private Function RandomString(By Val Stringlength As Byte) As String

Dim s As String = _
"0123456789ABCD EFGHIJKLMNOPQRS TUVWXYZabcdefgh ijklmnopqrstuvw xyz"
Dim sb As New System.Text.Str ingBuilder

Do
sb.Append(s.Cha rs(r.Next(0, 61)))
Loop While sb.Length < Stringlength

Return sb.ToString

End Function

My version generated 100000 * 255character strings in 4 secs as opposed to
yours (updated to use stringbuilder and default seeding for comparison)
taking 6 secs(making the Random object a Class level Private object reduced this to 5 secs). Without Stringbuilder yours took 23 secs and 21 secs.

Before that Random Class I used the old Rnd function and the fastest I could get, even using Stringbuilder, was 28 secs.

So I learned something useful Today.
Thankyou

Mick Doherty

"One Handed Man" <Bo****@Duck.ne t> wrote in message
news:bo******** **@titan.btinte rnet.com...

Try this - OHM

Public Class StringGenerator

Public Shared Function RandomString(le ngth As Integer) As String
Const zero As Integer = CInt("0"c)
Const nine As Integer = CInt("9"c)
Const capA As Integer = CInt("A"c)
Const capZ As Integer = CInt("Z"c)

Dim guid As Byte() = Guid.NewGuid(). ToByteArray()
Dim seed As Integer = guid(0) + Machine.Shift.L eft(guid(1), 8) +
Machine.Shift.L eft(guid(2), 16) + Machine.Shift.L eft(guid(3), 24)

Dim r As New Random(seed)

Dim s As String = Nothing
Dim i As Integer
For i = 0 To length - 1
Dim n As Integer
Do
n = r.Next(zero, capZ)
Loop While Not(n >= zero And n <= nine Or(n >= capA And n <=

capZ))

s += CChar(n)
Next i

Return s
End Function 'RandomString
End Class 'StringGenerato r


Crirus wrote:

Is there a function that return some random ID like string
alphanumeric? Like this:
A35sDsd1dSGsH

Thanks
Crirus