infix-notation

问题 I have been confused about this for a while, even despite reading the Scala Style Guide - Method Invocation several times. I want to be able to call this method def foldRVL[A,B](l: List[A], z: B)(f: (A, B) => B) = //"Right-Via-Left" l.reverse.foldLeft(z)((a, b) => f(b, a)) using dot notation like this List(1,2,3).foldRVL(0)(_ + _) . And not like this: foldRVL(List(1,2,3), 0)(_ + _) . Also, sometimes I've seen code that shows methods that actually either takes zero parameters in their

问题 I've been mulling over creating a language that would be extremely well suited to creation of DSLs, by allowing definitions of functions that are infix, postfix, prefix, or even consist of multiple words. For example, you could define an infix multiplication operator as follows (where multiply(X,Y) is already defined): a * b => multiply(a,b) Or a postfix "squared" operator: a squared => a * a Or a C or Java-style ternary operator, which involves two keywords interspersed with variables: a ? b

问题 I searched all over the internet for a good implementation in converting not numbers expressions but variable expressions from infix notation into prefix and postfix. All the searches I did weren't successful. Basically I want to see if there is any implementation yet in PHP so I could modify it to support more operators not only the (-,*,+,=). For example convert: a+b/c*(p/c) While keeping the variable names, and not having to enter numbers to evaluate them. 回答1: I have found a good

问题 There are many algorithms to convert infix to postfix all over the web. But my question is how to make that to support functions? For example sin(x+y)*z. I will appreciate a code. 回答1: If you are looking for an algorithm that gives you the conversion infix to postfix including function call support, you can use the below pseudocode(which looks like python code). I have written this for my case but not yet tested thouroughly. If you find any bugs please let me know. I have also written a Java

问题 It's difficult to tell what is being asked here. This question is ambiguous, vague, incomplete, overly broad, or rhetorical and cannot be reasonably answered in its current form. For help clarifying this question so that it can be reopened, visit the help center. Closed 7 years ago . I can not solve this expression from postfix to infix. Please help me to understand in detail 5 x y - / x y + 3 ^ 7 / + 回答1: postfix to infix: 5 x y - / x y + 3 ^ 7 / + STEP 5 x y - / A) 5xy-/ = 5 (x-y)/ = (5 /

问题 I am writing a package containing a function such as: "%IN%" <- function(x, table) x & match(x, table, nomatch = 0) > 0 When I Build & Reload the package (I use RStudio), this function is not available, as opposed to all other functions defined in the package. How do I make this work? 回答1: The solution entails installing roxygen2 and modifying the NAMESPACE file to include a line such as: export("%IN%") 来源： https://stackoverflow.com/questions/24660864/declaring-special-infix-functions-in-r

问题 I'm working on a project in Java that requires me to convert an infix expression to a postfix expression. I am currently able to convert infix expressions to postfix with this method as long as they don't contain parenthesis, but I can't figure out how to handle parenthesis. Basically, I have two stacks that hold objects that are called 'Token'. A Token is a wrapper class that holds a string that is either a number, variable (which gets evaluated as a number, pending on user input), operator

问题 I'm working on a project in Java that requires me to convert an infix expression to a postfix expression. I am currently able to convert infix expressions to postfix with this method as long as they don't contain parenthesis, but I can't figure out how to handle parenthesis. Basically, I have two stacks that hold objects that are called 'Token'. A Token is a wrapper class that holds a string that is either a number, variable (which gets evaluated as a number, pending on user input), operator

问题 I read book today. It introduced algorithm about chaning from infix to postfix.. What is benefits? Thanks in advance. 回答1: Well for one, you can easily evaluate a postfix expression in a single scan from left to right with the help of a stack, unlike evaluating infix expressions. and second, there is no need of the concept of parentheses and precedence rules etc. in a postfix expression. 回答2: I think infix is really easy to understand for human. Postfix is the good way for machine to process.

问题 I'm trying to make an RPN calculator. I have done the conversion from infix to postfix, now I want to evaluate the converted expression. When I enter any expression I get error String index out of range: 1. Here's my code with what I'm supposed to do in the program: static int eval(String postfix) { int result = 0; String temp2 = ""; int num1, num2, OPS; char operator; String delete = ""; for (int i = 0; i < postfix.length(); i++) { char M = postfix.charAt(i); // if v_i is an operand: Push v