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Questions tagged [expression]

Combination of several programming symbols and values intending to produce a result

An expression is code before it gets evaluated. That is, evaluating an expression will give you a result.

Expressions can consists of combinations of variables, constants, operators, function calls, or whatever constructs are available in that language.

Many s have an expression data type, and an evaluation function (often called eval), where calling eval(an_expression) will calculate a result.

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What are rvalues, lvalues, xvalues, glvalues, and prvalues?

In C++03, an expression is either an rvalue or an lvalue. In C++11, the two value categories have become five: rvalue lvalue xvalue glvalue prvalue What are these new categories of expressions, and why are they needed? How do these new categories…
James McNellis
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Expression Versus Statement

I'm asking with regards to c#, but I assume its the same in most other languages. Does anyone have a good definition of expressions and statements and what the differences are?
user1684
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What is the difference between an expression and a statement in Python?

In Python, what is the difference between expressions and statements?
wassimans
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Combining two expressions (Expression>)

I have two expressions of type Expression> and I want to take to OR, AND or NOT of these and get a new expression of the same type Expression> expr1; Expression> expr2; ... //how to do this (the code below…
BjartN
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What is this smiley-with-beard expression: "<:]{%>"?

I came across the following program, which compiles without errors or even warnings: int main(){ <:]{%>; // smile! } Live example. What does the program do, and what is that smiley-expression?
Xeo
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How to make Regular expression into non-greedy?

I'm using jQuery. I have a string with a block of special characters (begin and end). I want get the text from that special characters block. I used a regular expression object for in-string finding. But how can I tell jQuery to find multiple…
Rueta
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XPath find if node exists

Using a XPath query how do you find if a node (tag) exists at all? For example if I needed to make sure a website page has the correct basic structure like /html/body and /html/head/title.
EddyR
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How to split a long regular expression into multiple lines in JavaScript?

I have a very long regular expression, which I wish to split into multiple lines in my JavaScript code to keep each line length 80 characters according to JSLint rules. It's just better for reading, I think. Here's pattern sample: var pattern =…
Nik Sumeiko
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Are complex expressions possible in ng-hide / ng-show?

I want to do so: ng-hide="!globals.isAdmin && mapping.is_default" but the expression evaluates always to false. I do not want to define special function on $scope.
Paul
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How do I remove all non-ASCII characters with regex and Notepad++?

I searched a lot, but nowhere is it written how to remove non-ASCII characters from Notepad++. I need to know what command to write in find and replace (with picture it would be great). If I want to make a white-list and bookmark all the ASCII…
Texh
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What does i = (i, ++i, 1) + 1; do?

After reading this answer about undefined behavior and sequence points, I wrote a small program: #include int main(void) { int i = 5; i = (i, ++i, 1) + 1; printf("%d\n", i); return 0; } The output is 2. Oh God, I didn't see the…
gsamaras
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Why was the statement (j++); forbidden?

The following code is wrong (see it on ideone): public class Test { public static void Main() { int j = 5; (j++); // if we remove the "(" and ")" then this compiles fine. } } error CS0201: Only assignment, call,…
user10607
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Assignment inside lambda expression in Python

I have a list of objects and I want to remove all objects that are empty except for one, using filter and a lambda expression. For example if the input is: [Object(name=""), Object(name="fake_name"), Object(name="")] ...then the output should…
Cat
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converting a .net Func to a .net Expression>

Going from a lambda to an Expression is easy using a method call... public void GimmeExpression(Expression> expression) { ((MemberExpression)expression.Body).Member.Name; // "DoStuff" } public void SomewhereElse() { …
Dave Cameron
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C# Float expression: strange behavior when casting the result float to int

I have the following simple code : int speed1 = (int)(6.2f * 10); float tmp = 6.2f * 10; int speed2 = (int)tmp; speed1 and speed2 should have the same value, but in fact, I have : speed1 = 61 speed2 = 62 I know I should probably use Math.Round…
Baalrukh
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