evaluate

问题 I need to write a TSQL user defined function which will accept a string and return a number. I will call the function like dbo.EvaluateExpression('10*4.5*0.5') should return the number 22.5 Can any one help me to write this function EvaluateExpression . Currently I am using CLR function which I need to avoid. Edit1 I know this can be done using stored procedure, but I want to call this function in some statements ex: select 10* dbo.EvaluateExpression('10*4.5*0.5') Also I have around 400,000

问题 Say I have a string, $char. $char == "*". I also have two variables, $a and $b, which equal "4" and "5" respectively. How do I get the result of $a $char $b, ie 4 * 5 ? Thanks :) 回答1: You can use eval() as suggested by @konforce, however the safest route would be something like: $left = (int)$a; $right = (int)$b; $result = 0; switch($char){ case "*": $result = $left * $right; break; case "+"; $result = $left + $right; break; // etc } 回答2: safest method is a switch construct: function my

问题 Okay lets say I have a string such as this in a text file: ((( var1 AND var2 AND var3) OR var4) AND ((var5 OR var6) AND var7)) after parsing this into the c program and the vars are handled and set correctly it will end up looking something like this: ((( 1 AND 0 AND 0) OR 1) AND ((0 OR 1) AND 1)) Are there any useful libraries out there for evaluating expressions that are represented as one string like this? I was thinking I could just call a perl program with the string as an argument that

问题 I\'m trying to pass a variable into a page.evaluate() function in Puppeteer, but when I use the following very simplified example, the variable evalVar is undefined. I\'m new to Puppeteer and can\'t find any examples to build on, so I need help passing that variable into the page.evaluate() function so I can use it inside. const puppeteer = require(\'puppeteer\'); (async() => { const browser = await puppeteer.launch({headless: false}); const page = await browser.newPage(); const evalVar = \

问题 I have 0,4*A1 in a cell (as a string). How can convert this \"string formula\" into a real formula and calculate its value, in another cell? 回答1: Evaluate might suit: http://www.mrexcel.com/forum/showthread.php?t=62067 Function Eval(Ref As String) Application.Volatile Eval = Evaluate(Ref) End Function 回答2: I Concatenated my formula as normal but at the start I had '= instead of = . Then I copy and paste as text to where I need it. Then I highlight the section saved as text and press ctrl + H

问题 This question already has an answer here: Is it possible to compile and execute new code at runtime in .NET? 15 answers Is there a function the .NET framework that can evaluate a numeric expression contained in a string and return the result? F.e.: string mystring = \"3*(2+4)\"; int result = EvaluateExpression(mystring); Console.Writeln(result); // Outputs 18 Is there a standard framework function that you can replace my EvaluateExpression method with? 回答1: Yes, you can let C# compiler

问题 I have the following piece of code: $item[\'price\'] = 0; /*code to get item information goes in here*/ if($item[\'price\'] == \'e\') { $item[\'price\'] = -1; } It is intended to initialize the item price to 0 and then get information about it. If the price is informed as \'e\' it means an exchange instead of a sell, which is stored in a database as a negative number. There is also the possibility to leave the price as 0, either because the item is a bonus or because the price will be set in