Question

Jquery是否有更简单/更短的方式来编写这样的if语句：

if(number === "0" ) { degrees = "-160"; }
if(number === "1" ) { degrees = "-158"; }
if(number === "2" ) { degrees = "-156"; }
if(number === "3" ) { degrees = "-154"; }
if(number === "4" ) { degrees = "-152"; }
if(number === "5" ) { degrees = "-150"; }
if(number === "6" ) { degrees = "-148"; }
if(number === "7" ) { degrees = "-146"; }
if(number === "8" ) { degrees = "-144"; }
if(number === "9" ) { degrees = "-142"; }
if(number === "10") { degrees = "-140"; }

数字变量只是一个输入字段，用户输入0到10之间的数字。

谢谢！

Answer 1

对于您的具体问题，您只需编写一个函数，如下所示

var getDegrees = function(number){
   return -160 + ((+number)*2);
}

并将其称为贝娄

getDegrees("1") // will return -158
getDegrees("10") // will return -140
getDegrees(10) // will also return -158

Answer 2

嗯......使用数组快速简便。

degress = -160 + 2 * number;

或者，为了避免将值硬编码到代码中，请尝试创建一个根据公式生成值的函数。

robot pick rubbish

Answer 3

创建一个数组而不是if。

var degrees = ["-160","-158","-156","-154","-152","-150","-148","-146","-144","-142","-140"];

然后你可以用

输出正确的度数

console.log(degrees[number]);

Answer 4

使用swich

switch(number ) { 
case "0":degrees = "-160"; 
       break;
case "1" : degrees = "-158"; 
       break;
...
...

case "10" : degrees = "-140";
     break;
}

Answer 5

switch语句可能适合你

switch(number){
    case 1:
       doThis();
       break;
    case 2:
       doThat();
       break;
}

Answer 6

试

  var num=-160;
    if(number >= "0" and number <= "10" ){
        degree = num+ (number *2); // diff is 2
    }

或者您可以使用简单的一行

 degree = -160 + (number * 2)

Answer 7

您可以使用下面创建的地图，并使用number变量

来检索值

var map = new Object();
map["0"]="-160";
map["1"]="-158"; 
map["2"]="-156"; 
map["3"]="-154"; 
map["4"]="-152"; 
map["5"]="-150"; 
map["6"]="-148"; 
map["7"]="-146"; 
map["8"]="-144"; 
map["9"]="-142";
map["10"]="-140";

和反复值，如

degrees = map[number];

Answer 8

对我来说，我喜欢这样使用：

var obj = {
   0 : '-160',
   1 : '-158'
}

if ( $.inArray(number, [1,2,3,...10] ) !== -1 ) {
   degree = obj[number];
}

Answer 9

为什么你不使用switch-case块？

switch (number) {
    case "0":
        degrees = "-160";
    case "1":
        degrees = "-158";
        .
        .
        .
    default:
    }

但是您可以将数字转换为int。那么你只需要编写这个命令：

degrees = "-" + 160 - number * 2;

Answer 10

使用对象，如下所示：

 var myObject = {'0':'-160', '1':'-158', '2':'-156'};

 var degrees = myObject[number];

Answer 11

尝试创建具有属性0 - 10的对象，将degrees设置为对象中属性的值

var obj = {
  "0": "-160",
  "1": "-158",
  "2": "-156",
  "3": "-154",
  "4": "-152",
  "5": "-150",
  "6": "-148",
  "7": "-146",
  "8": "-144",
  "9": "-142",
  "10": "-140"
};

// set pseudo-random number
var number = 1 + Math.floor(Math.random() * 10);

// set `degrees` 
var degrees = obj[number];

document.body.textContent = degrees;

Answer 12

这个怎么样？

degrees = ( -160 + 2 * number ).toString();

var number = "3";
var degrees = ( -160 + 2 * number ).toString();

console.log( number, degrees );

Answer 13

所以，我有几种方法可以回答这个问题。它不是更短，但您的意图可能更明显，更直接的是switch而不是if s：

switch (number)
{
    case "0":
        degrees = "-160";
        break;
    case "1":
        degrees = "-158";
        break;
    ...
}

但是，对于这种类型的事情，查找表可能更清晰简洁：

var degreesLookupTable = {
    "0": "-160",
    "1": "-158",
    "2": "-156",
    "3": "-154",
    "4": "-152",
    "5": "-150",
    "6": "-148",
    "7": "-146",
    "8": "-144",
    "9": "-142",
    "10": "-140"
};

if (number in degreesLookupTable)
    degrees = degreesLookupTable[number]
else
    throw "Number not found in degree map!"

有关详细信息，请参阅查找表部分here。

第三，number和degrees之间似乎存在直接的数学关系。也许只需编写一个函数来直接根据degrees？

的值计算number

编写Jquery If语句的更短方法“IF”

13 个答案: