Is there a method that allows me to evaluate a mathematical expression in a string? Example (Not actual Code):
Input = "2+2"
Output = SomeMethod(Input)
Output = 4
Update: Nevermind, I found a way around it by using DataTable.Compute.
Does anybody know of a call in vb.net that will evaluate a string expression. For example, how would one evaluate the expression "(1+2)*(3+4)"?I've looked all over and it seems that people are writing their own parsers. There has to be a better way. After all these years, VB.Net must have something that will take an expression and evaluate it.
Dim strMyExpression as string = "(1+2)*(3+4)"
msgbox( VBEvaluate(strMyExpression))
and the result would be 35.Also, when will microsoft start to use google as the search engine for these forums? Bing really sucks. Searching for "Evaluating a string expression in VB.net" gives the most bizarre links.
I have a application that allows the user to enter a series of nested filtering commands. E.g "Name starts with x or ((Description contains y or Property1 is On) and Property2 > 100)"
I can preprocess this and distill it down to a string in the form of an expression of True and False's ie, To "True or ((False or True) and False)" Is there a simple way to have this final expression evaluated without having to write a complex evaluator myself?
I have seen a method of evaluating this by compiling a dummy function at runtime but as I need to process this against possibly thousands of records that solution is too slow.
BTW These are not all fields in a database so I cannot use Queries or SQL etc.
I am making a simple calculator that will evaluate functions I have a entry box and the user types in simple equations i.e. 1+4*3/5=? how would i make this evaluate the string?
View 7 RepliesI am trying to figure out a way to set a string equal to vb code and then run that string as a line a of vb code.
for example
set string x = "TextBox1.Text =
"test1".ToString"
[code]....
I'm working on a project where I need to evaluate some formulas in VB.NET. I've been using the MS Script Control to evaluate some of the simple logical/mathematical formulasHowever, I'm now faced with dealing with string expressions that set variables in my program to certain values. So, for example, let's say I've got the following:
Dim netPrice As Decimal
Dim expressionFormula As String = "netPrice = 0"
[code]....
I must convert string data from a CNC that is arithmetic expression to a number that I can use in a VB application that I wrote. The following is what I get out of the cnc. [18722*65536+19377]/67108864. I need to evaluate this expression in my VB ap. The format of the string is not always the same as what I have illustrated.
View 2 RepliesI need a regular expression that can validate that a string is an alphanumeric comma delimited string.
Examples:
123, 4A67, GGG, 767 would be valid.
12333, 78787&*, GH778 would be invalid
fghkjhfdg8797< would be invalid
This is what I have so far, but isn't quite right: ^(?=.*[a-zA-Z0-9][,]).*$
I want to use "*" or "" as mathematical operators as such:
[code...]
this in one line without building a long, complex function? I would also like for this to be something that is already a part of the VB.NET structure and doesn't require an import.If such a solution does not exist how do I do it with a function or .dll import?
So I am trying to evaluate 3 conditions in an if statement. Its not working how I would assume it should. I basically want to do this:vb.net If PGN = &HEF007E And PGNData(0) = &H58 And (PGNData(1) And &H40) = &H40 Then IgnOn = True Else IgnOn = False If I write it in that manner it gives inconsistent results. If I workaround by writing it this way it works perfectly:vb.net If PGN = &HEF007E And PGNData(0) = &H58 Then If (PGNData(1) And &H40) = &H40 Then IgnOn = True Else IgnOn = False
View 1 Replieshow can I use a string ( string = "my.resources.imagename" ) as an expression? like this:
dim imageString as string = "my.resources." + name 'name will be declared and is the name of the person of who the picture in the resources is picturebox1.image = (expression from string here)
is this possible? if yes, how then? I searched all over the internet but I couldn't find it
im doing a simple calculatro and was happy with the way i done things .. a ew member variables and a properties:
Private MVAR_Number1 As Decimal
Private MVAR_Number2 As Decimal
Private MVAR_Operator As Char[code].....
he want to add this:
Dim Operators() As Char = ("+", "-", "*", "/")
Dim OpPos as Decimal
OpPos = Expr.IndexOfAny(Operators)[code].....
Just drives me mad how complex this is all getting for something so simple, fell like giving it all up .
I have like a three word expression: "Shut The Door" and I want to find it in a sentence. Since They are kind of separated by space?
View 6 RepliesI want to match a string for example "yes" but where it is not in brackets so that the following would be matched: yes (bla yes bla) bla yes
View 7 RepliesI want a regular expression for the following issue:I want to match a string that contains A,B,C,D,E and F. string length should be 0 to 6. and not character should be repeat in the string.Example: ABCDEF, ACDEFB, EFBCDA, etc. but not ABBCDES/W Engineer
View 3 Repliesfrom the Help in VS 2008: Replace: Returns a string in which a specified substring has been replaced with another substring a specified number of times.
Expression
Required. String expression containing substring to replace.
Find
Required. Substring being searched for.
Replacement
Required. Replacement substring.
Start
Optional. Position within Expression where substring search is to begin. If omitted, 1 is assumed.Count Optional. Number of substring substitutions to perform. If omitted, the default value is 1, which means "make all possible substitutions."
Compare Optional. Numeric value indicating the kind of comparison to use when evaluating substrings. See Settings for values.
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In a Select Case statement is there a way to test if an expression contains a part of a string? Something like this:
Select Case myString
Case "*abc*" 'any string that contains "abc" falls here
Case "*def*" 'etc
End Select
My DGV's last visible column in a boolean. I am needing to go through each row and determine if the value of dgv item bFlag is true then turn the row back ground red. Here is my start of it. It appears to be only making one loop then giving the message box.
Private Sub EvalGrid()
BindDGV(dgvResults)
Dim cnt As Integer = dgvResults.Rows.Count
[Code]....
I store a formula in the database such as the following:GrossIncome+(Overtime/0.5)-Deductions=BasicNetIncome
I am able to substitute the string representations with actually values entered, thus:1000+(150*0.5)-100=BasicNetIncome
Then I remove the '=BasicNetIncome', thus:
1000+(150*0.5)-100
How can evaluate the above equation to return a result:
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Private Sub Button4_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button4.Click
With Me.PrintForm1
[Code]....
I'm looking to create an inline function (method) inside my NVelocity template. The solution to this appears to be to use Velocimacros. So, I mocked up the following template to test:
#macro( getOutput $one $two $three )
<td>$one</td>
<td>$two.Item2</td>
<td>$three</td>
#end
[Code] .....
When I run the template, the problem I'm having is that the output from the macro parameter $three is literally "$item.Item3" instead of evaluating to #3/3/2003#. (BTW - this happens with any of the 3 items in the tuple if they are passed with the .Item call, so it isn't about the data type). I can make a variable and pass it just fine ($one1). I can pass the tuple itself and call the .Item property inside the macro ($item.Item2), but for some reason I cannot call the .Item property when passing the argument to the macro.
We are working on a poker game as a class project. My part is to evaluate and then determine the value of a players hand. We are evaluating from highest to lowest (ie. determining whether the player has a straight flush, 4 of a kind, full house, flush and then going all the way down to a high card only "worthless hand"). My part is evaluating the 2 pair, 1 pair, and nothing hands. The hand will be a two-dimensional array with the row(0 thru 12),column (0) containing the numeric "face" value of the cards and the column(1) containing the value assigned to the suite (1=clubs, 2=diamonds,3=hearts,4=spades). I have NO IDEA where to even begin this evaluating procedure.
View 4 RepliesI am making a checkers program and I am in the phase of starting to evaluate jumps. This is what I currently have so far and allow me to fill you in a bit before you look at the code. Checker pieces are white/green. Each checker is created as a label at runtime and in the tag property a struct is held that possesses all of the information reguarding current and previous checker state.
The problem I am having is that as this sub runs each opposing checker is evaluated for jump capabilites which is all fine and dandy. It is even alright that currently if a jump is executed that the same side will continue to evaluate through the sub looking for additional jumps and if they are found they will be made because that is how it is currently coded. What I am trying to do is find a way to evaluate each piece that can jump. So if checker1 can only make one jump and checker2 can make a triple jump checker2 needs to be the guy making the jump and I honestly don't know how do start that. I am forseeing global vars being created to hold information or even a structure and taking the one that changes the most. If two checkers can only make 1 jump then I will rand the one that gets to jump (not looking to win any awards for AI here). Anyhow, any suggestions on how to start this, at least saving the information throughout the sub even if it is called recursively?
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I'd like to understand why one type can't be converted to another type inside a constant expression.
View 13 RepliesI understand the concept of regular expressions but I am looking for a regular expression string that checks the input string for the following criteria only...
1.) Upper and lower case letters
2.) The space character
3.) Apostrophe
4.) Comma
5.) Period
6.) Hyphen
Ok - this may seem like a strange request ... but basically I need a regular expression to return a string in between two brackets as described below... String:
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I am trying to use a regular expression to find a certain string within a textbox.
Is it possible to include the equals sign (=) within the regex so it looks for this? When i type the equals sign within the regex it doesn't fnid it any more.
Works when searching this string - "and JobID 816138</Detail>":
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How can I print a mathematical formula in a form? For a example I found in wikipedia a guide to do it in HTML: [url]
[URL]
But how can I do it in VB2008, showing the formula in a form?
i need mathematical calculation model code.
View 2 Repliesi got bored earlier so instead of doing my Maths homework i thought what the hell why dont i make a program to do it for me. The problem is im getting an error with my NCR function.For those of you who dont know NCR is used in calculating Statistics generally it goes like this
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