comparison-operators

问题 I can't seem to find reference on why does this not work: - (2000,1)<(2000,1); stdIn:18.1-18.18 Error: operator and operand don't agree [overload] operator domain: 'Z * 'Z operand: (int * int) * (int * int) in expression: (2000,1) < (2000,1) Does Standard ML support structural comparison? 回答1: The short answer: Only for equality. The strictly less than operator (<) in the top level environment is as the other comparison operators a bit "special". They are "special" in the way that they are

问题 In vanilla Scala the following assertions pass assert(1D > 0F) assert(1F > 0) assert(1L > 0) assert(1 > 0.toShort) assert(1.toShort > 0.toChar) however similar matchers in ScalaTest fail 1D shouldBe > (0F) 1F shouldBe > (0) 1L shouldBe > (0) 1 shouldBe > (0.toShort) 1.toShort shouldBe > (0.toChar) A workaround is to make both sides the same type, for example 1D shouldBe > (0D) Why does it work in Scala, but not in Scalatest, or what is it about the signature of > def >[T : Ordering] (right: T

问题 What am I missing here? This script looks right to me. But for some reason when I send it a zipcode of 02897 (or anything that should be Rhode Island), it returns New Hampshire. Aside from political beliefs Javascript developers may have (sure most people would prefer to live in New Hampsire than Rhode Island), why doesn't this script work? New Jersey and Alabama work fine. Why can't Rhode Island get some love? function getState(zip) { var thiszip = zip; // parseInt(zip); if (thiszip >= 35000

问题 In C/C++, comparison operators such as < > have higher priority than == does. This code will evaluate to true or 1 : if(3<4 == 2<3) { //3<4 == 2<3 will evaluate to true ... } But in Python, it seems wrong: 3<4 == 2<3 #this will evaluate to False in Python. In Python, does every comparison operator have the same priority? 回答1: In Python, not only do comparison operators gave the same priority, they are treated specially (they chain rather than group). From the documentation: Formally, if a, b,

问题 I mathematics, x <= y is equivalent to !(x > y) . This is true for floating-point arithmetic, in most cases , but not always. When x or y is NaN, x <= y is not equivalent to !(x > y) , because comparing a NaN to anything always returns false . But still, x <= y <=> !(x > y) is true most of the time. Now, suppose I am writing a class that contains floating-point values, and I want to define comparison operators for this class. For definiteness, suppose I am writing a high-precision floating

问题 Without specifying the equality comparison properties of objects, Python is still doing something when using > and < . What is Python actually comparing these objects by if you don't specify __gt__ or __lt__ ? I would expect an unsupported operand error here, as you get when trying to add two objects together without defing __add__ . In [1]: class MyObject(object): ...: pass ...: In [2]: class YourObject(object): ...: pass ...: In [3]: me = MyObject() In [4]: you = YourObject() In [5]: me >

问题 Couldn't find much on this. Trying to compare 2 values, but they can't be equal. In my case, they can be (and often are) either greater than or less than. Should I use: if a <> b: dostuff or if a != b: dostuff This page says they're similar, which implies there's at least something different about them. 回答1: Quoting from Python language reference, The comparison operators <> and != are alternate spellings of the same operator. != is the preferred spelling; <> is obsolescent. So, they both are

问题 I'm trying to use javascript to select the greater of two numbers. I know I can write an if statement, but I'm wondering if there's some sort of Math operation or something to make this more efficient. Here's how I'd do it with an if statement: if (a > b) { c = a; } else { c = b; } 回答1: You're looking for the Max function I think.... var c = Math.max(a, b); This function will take more than two parameters as well: console.log(Math.max(4,76,92,3,4,12,9)); //outputs 92 If you have a array of

问题 I need to run several queries against columns containing both positive and negative numbers and return all rows that are either < or > than a selected value, however it's not returning the expected results when I use a 'Greater than' operator if the selected value is a negative number. Please note that when the selected value is a negative number it should be returning both positive and negative numbers, and it seems to be excluding the negative numbers from the results. SELECT T3.* FROM

问题 This is my first time on Stack Overflow and I am trying to understand what '=' means in the last line of this code: Dim label As Label = Me.labels.Item(String.Concat(New Object() { movimiento.Sector1.ID, "-", movimiento.X1, "-", movimiento.Y1 })) Dim dictionary As Dictionary(Of Label, Integer) Dim label3 As Label dictionary = Me.demandas2.Item(label3 = label) = (dictionary.Item(label3) - 1) Any kind of help will be welcome, thanks in advance! 回答1: The equals sign ( = ) is used for two