I'm trying to split a string of 32 numerical characters into a 16 length Array of Byte and each value has to stay numerical
from "70033023311330000000004195081460" to array {&H_70, &H_03, &H_30, &H_23, ..}
I've tried multiple stuff but each time either it's the conversion that's wrong or I can't find the appropriate combination of functions to implement it.
'it splits but per 1 character only instead of two
str.Select(Function(n) Convert.ToByte(n, 10)).ToArray
'I also tried looping but then the leading zero disappears and the output is a string converted to HEX which is also not what I want.
Function ConvertStringToHexBinary(str As String) As Byte()
Dim arr(15) As Byte
Dim k = 0
For i As Integer = 0 To str.Length - 1
arr(k) = str(i) & str(i + 1)
k += 1
i += 1
Next
Return arr
End Function
Anyone got any suggestion what to do?
G3nt_M3caj's use of LINQ might be.. er.. appealing to the LINQ lovers but it's horrifically inefficient. LINQ is a hammer; not everything is a nail.
This one is about 3 times faster than the LINQ version:
Dim str As String = "70033023311330000000004195081460"
Dim byt(str.Length/2) as Byte
For i = 0 to str.Length - 1 Step 2
byt(i/2) = Convert.ToByte(str.Substring(i, 2))
Next i
And this one, which does it all with math and doesn't do any new stringing at all is just under 3 times faster than the above (making it around 9 times faster than the LINQ version):
Dim str As String = "70033023311330000000004195081460"
Dim byt(str.Length / 2) As Byte
For i = 0 To str.Length - 1
If i Mod 2 = 0 Then
byt(i / 2) = (Convert.ToByte(str(i)) - &H30) * &HA
Else
byt(i / 2) += Convert.ToByte(str(i)) - &H30
End If
Next i
Of the two, I prefer the stringy version because it's easier to read and work out what's going on - another advantage loops approaches often have over a LINQ approach
Do you need something like this?
Dim str As String = "70033023311330000000004195081460"
Dim mBytes() As Byte = str.
Select(Function(x, n) New With {x, n}).
GroupBy(Function(x) x.n \ 2, Function(x) x.x).
Select(Function(y) Convert.ToByte(New String(y.ToArray()), 10)).ToArray
Related
I'm working under MS-Visio 2010 in VBA (not an expert) and I want to generate a random number (several numbers would be even better) based on a string as seed.
I know that Rnd(seed) with seed as a negative number exists. However, I don't know about any random generator with a string as seed. Maybe some kind of hash function with a number as result ?
I'd like something like :
print function("abc")
45
print function("xyz abc-5")
86
print function("abc")
45
with spaces, symbols and numbers support when inside the seed string.
I may see a workaround by converting each character to some ascii number corresponding and somehow using this big number as seed with Rnd but it definitely feels far-fetched. Does anyone knows of a fancier way of doing so ?
Combined these examples
VBA hash string
Convert HEX string to Unsigned INT (VBA)
to:
Function hash4(txt)
' copied from the example
Dim x As Long
Dim mask, i, j, nC, crc As Integer
Dim c As String
crc = &HFFFF
For nC = 1 To Len(txt)
j = Asc(Mid(txt, nC)) ' <<<<<<< new line of code - makes all the difference
' instead of j = Val("&H" + Mid(txt, nC, 2))
crc = crc Xor j
For j = 1 To 8
mask = 0
If crc / 2 <> Int(crc / 2) Then mask = &HA001
crc = Int(crc / 2) And &H7FFF: crc = crc Xor mask
Next j
Next nC
c = Hex$(crc)
' <<<<< new section: make sure returned string is always 4 characters long >>>>>
' pad to always have length 4:
While Len(c) < 4
c = "0" & c
Wend
Dim Hex2Dbl As Double
Hex2Dbl = CDbl("&h0" & c) ' Overflow Error if more than 2 ^ 64
If Hex2Dbl < 0 Then Hex2Dbl = Hex2Dbl + 4294967296# ' 16 ^ 8 = 4294967296
hash4 = Hex2Dbl
End Function
Try in immediate (Ctrl + G in VBA editor window):
?hash4("Value 1")
31335
?hash4("Value 2")
31527
This function will:
return different number for different input strings
sometimes they will match, it is called hash-collisions
if it is critical, you can use md5, sha-1 hashes, their examples in VBA also available
return same number for same input strings
I'm using this query in vb.net
Raw_data = Alltext_line.Substring(Alltext_line.IndexOf("R|1"))
and I want to increase R|1 to R|2, R|3 and so on using for loop.
I tried it many ways but getting error
string to double is invalid
any help will be appreciated
You must first extract the number from the string. If the text part ("R") is always separated from the number part by a "|", you can easily separated the two with Split:
Dim Alltext_line = "R|1"
Dim parts = Alltext_line.Split("|"c)
parts is a string array. If this results in two parts, the string has the expected shape and we can try to convert the second part to a number, increase it and then re-create the string using the increased number
Dim n As Integer
If parts.Length = 2 AndAlso Integer.TryParse(parts(1), n) Then
Alltext_line = parts(0) & "|" & (n + 1)
End If
Note that the c in "|"c denotes a Char constant in VB.
An alternate solution that takes advantage of the String type defined as an Array of Chars.
I'm using string.Concat() to patch together the resulting IEnumerable(Of Char) and CInt() to convert the string to an Integer and sum 1 to its value.
Raw_data = "R|151"
Dim Result As String = Raw_data.Substring(0, 2) & (CInt(String.Concat(Raw_data.Skip(2))) + 1).ToString
This, of course, supposes that the source string is directly convertible to an Integer type.
If a value check is instead required, you can use Integer.TryParse() to perform the validation:
Dim ValuePart As String = Raw_data.Substring(2)
Dim Value As Integer = 0
If Integer.TryParse(ValuePart, Value) Then
Raw_data = Raw_data.Substring(0, 2) & (Value + 1).ToString
End If
If the left part can be variable (in size or content), the answer provided by Olivier Jacot-Descombes is covering this scenario already.
Sub IncrVal()
Dim s = "R|1"
For x% = 1 To 10
s = Regex.Replace(s, "[0-9]+", Function(m) Integer.Parse(m.Value) + 1)
Next
End Sub
Examples:
Double-Number is 56.6789 result should be 4
Double-Number is 12345.67 result should be 2
Double-Number is 12345.6 result should be 1
I have a solution tinkering with strings, but I think there is an mathematical solution?
Please in VB.NET ...
Split the original number and get the length of the upper index (1)
myNumber = 12.3456
Dim count As Integer = Len(Split(CStr(myNumber), Application.DecimalSeparator)(1))
Debug.Print count // prints '4'
edit: replaced "." with decimal separator to ensure use across varying cultures
You can try like this:
Dim x As String = CStr(56.6789)
Dim count = x.Length - InStr(x, ".")
One way to do it is to keep knocking off the whole part, multiplying by 10, repeat until you have an integer:
Dim x As Double = 1.23456
Dim count As Integer = 0
While Math.Floor(x) <> x
x = (x - Math.Floor(x)) * 10D
count = count + 1
End While
Note this will fail if there is an infinite number of decimal places - so you could set a limit on it (If count > 100 Then Exit While)
Another way would be like this, which converts to a string but removes the need to hardcode the separator.
Dim x As Double = 1.23456
Dim x0 As Double = x - Math.Floor(x)
Dim x0String As String = x0.ToString()
Dim count As Integer = x0String.Substring(2, x0String.Length - 2).Length
Using Application.DecimalSeparator also allows a string to be used.
The method with a string will again lose information about an infinite-length fractional part, as it will truncate it.
I need to compare phone numbers from a CSV file to phone numbers in an SSMS database in VB6 without using the .Net Library. One may have a number as 555-555-5555 and the other may have the same number as (555) 555-5555 which obviously kicks back as different when strings are compared.
I know I can use for loops and a buffer to pull out only numeric characters like:
Public Function PhoneNumberNumeric(PhoneNumberCSV As String) As String
Dim CharNdx As Integer
Dim buffer As String
For CharNdx = 1 To Len(PhoneNumberCSV) Step 1
If IsNumeric(Mid(PhoneNumberCSV, CharNdx, 1)) Then
buffer = buffer + Mid(PhoneNumberCSV, CharNdx, 1)
End If
Next
PhoneNumberNumeric = buffer
End Function
but this is expensive. Is there a less expensive way to do this?
This should be a bit quicker:
Private Function Clean(ByRef Original As String) As String
Dim I As Long
Dim J As Long
Dim Char As Long
Clean = Space$(10)
For I = 1 To Len(Original)
Char = AscW(Mid$(Original, I, 1))
If 48 <= Char And Char <= 57 Then
J = J + 1
If J > 10 Then Exit For 'Or raise an exception.
Mid$(Clean, J, 1) = ChrW$(Char)
End If
Next
End Function
It avoids string concatenation, ANSI conversions, and VBScript-form "pigeon VB" (use of slow Variant functions).
I have a variable that holds a string "02100030000000000000000000D5010008D501000804" and I'm byte separating the string using
For i As Integer = 1 To (stringReader.Length - 1) Step 2
'Get the successive 2-character substrings, parse as bytes and add to total
Dim b As Byte = Byte.Parse(stringReader.Substring(i, 2), NumberStyles.AllowHexSpecifier)
sum = sum + CInt(b)
Next
I'm converting the strings to direct integers.e.g:(string"10" to Integer10 and ). That works fine. But Whenever I convert the string"02" to Integer, I get only Integer(2) and I need Integer(02). How can I proceed with?
My code is:
stringReader = fileReader.ReadLine()
byt = stringReader(1) + stringReader(2)
stringreader contains something like "100030000000000000000000D5010008D501000804"
Byte separation
For i As Integer = 1 To (stringReader.Length - 1) Step 2
'Get the successive 2-character substrings, parse as bytes and add to total
Dim b As Byte = Byte.Parse(stringReader.Substring(i, 2), NumberStyles.AllowHexSpecifier)
sum = sum + CInt(b)
Next
You can use
number.ToString("D2")
where number is an integral type like System.Int32(Integer).
Further reading: Standard Numeric Format Strings: The Decimal ("D") Format Specifier
If you have a String instead you could also use String.PadLeft:
"2".PadLeft(2, "0"c) ' -> "02"