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JavaScript 使用对象进行查找值

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对象和字典一样,可以用来存储键/值对。如果你的数据跟对象一样,你可以用对象来查找你想要的值,而不是使用switch或if/else语句。当你知道你的输入数据在某个范围时,这种查找方式极为有效。


这是简单的反向字母表:



var alpha = {

1:"Z",

2:"Y",

3:"X",

4:"W",

...

24:"C",

25:"B",

26:"A"

};

alpha[2]; // "Y"

alpha[24]; // "C"

var value = 2;

alpha[value]; // "Y"

?例:
switch语句查找:

function phoneticLookup(val) {
var result = "";
switch(val) {
case "alpha":
result = "Adams";
break;
case "bravo":
result = "Boston";
break;
case "charlie":
result = "Chicago";
break;
case "delta":
result = "Denver";
break;
case "echo":
result = "Easy";
break;
case "foxtrot":
result = "Frank";
}
return result;
}
phoneticLookup("charlie");


?


?


对象查找:

function phoneticLookup(val) {
var result = "";
var lookup={
??? "alpha":"Adams",
??? "bravo":"Boston",
??? "charlie":"Chicago",
??? "delta":"Denver",
??? "echo":"Easy",
??? "foxtrot":"Frank"
}
result = lookup[val];
return result;

phoneticLookup("charlie");


?输出结果:Chicago



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