I think you’re looking for something like this: SET @queryString = ( SELECT CONCAT(‘INSERT INTO user_group (`group_id`,`user_id`) VALUES ‘, www.vals) as res FROM ( SELECT GROUP_CONCAT(qwe.asd SEPARATOR ‘,’) as vals FROM ( SELECT CONCAT(‘(59,’, user_id, ‘)’) as asd FROM access WHERE residency = 9 ) as qwe ) as www ); PREPARE stmt FROM @queryString; … Read more
Someone else added this and then it got deleted. I thought it was pretty cool because no 3rd party libraries required. class Program { static void Main(string[] args) { Console.WriteLine(Evaluate(“(4+8)*2”)); Console.ReadKey(); } public static double Evaluate(string expression) { DataTable table = new DataTable(); table.Columns.Add(“expression”, typeof(string), expression); DataRow row = table.NewRow(); table.Rows.Add(row); return double.Parse((string)row[“expression”]); } }
Further to Thomas’s answer, it’s actually possible to access the (deprecated) JScript libraries directly from C#, which means you can use the equivalent of JScript’s eval function. using Microsoft.JScript; // needs a reference to Microsoft.JScript.dll using Microsoft.JScript.Vsa; // needs a reference to Microsoft.Vsa.dll // … string expr = “7 + (5 * 4)”; Console.WriteLine(JScriptEval(expr)); // … Read more
No, function parameters are not evaluated in a defined order in C. See Martin York’s answers to What are all the common undefined behaviour that c++ programmer should know about?.
Use a lookup table: import operator ops = { “+”: operator.add, “-“: operator.sub } # etc. print(ops[“+”](1,1)) # prints 2
TL;DR: They are different; use list when in doubt. A rule of thumb: use list whenever you want the arguments to be evaluated; quote “distributes” over its arguments, so ‘(+ 1 2) is like (list ‘+ ‘1 ‘2). You’ll end up with a symbol in your list, not a function. An in-depth look at list … Read more
ArrayList implements the List Interface. If you look at the Javadoc for List at the contains method you will see that it uses the equals() method to evaluate if two objects are the same.