开发者

JavaScript associate array

In Python I could do something like myMap = {key: [value1, value2]} and then access the value2 using myMap[key][1]

Can I do something like this in JavaScrip开发者_如何学Pythont?


Well, you can do this:

var myMap = { key: [ value1, value2 ] };
var array = myMap.key; // or myMap["key"]

JavaScript doesn't have an "associative array" type, one that combines "map" behavior with array behavior like keeping track of the number of properties. Thus the common thing to do is use a plain object. In modern JavaScript now (2017), there's an explicit Map facility that allows keys to be of any type, not just strings as when using simple objects.

JavaScript is a little bit silly about the object literal notation, in that it won't let you use reserved words for keys unless you quote them:

var myMap = { 'function': 'hello world' };

The quote syntax allows any string to be used as a property name. To access such properties, you'd use the [ ] operator

console.log(myMap["function"]); // "hello world"


It is indeed.

var myMap = {london: ['clapham', 'chelsea'], bristol:['clifton', 'redland']}

alert(myMap.london[0]);
alert(myMap['bristol'][1]);

See this example on jsFiddle


Yes, and the syntax is almost the same too.

var myMap = {key: ["value1", "value2"]};
alert(myMap["key"][1]); // Pops up an alert with the word "value2"

You can also use the following notation:

myMap.key[1]


Short answer... yes...

var m = { Foo : ["Bar", "Baz"] };

alert(m.Foo[0]);
alert(m["Foo"][1]);


You can use Map:

var myMap = new Map();
myMap.set('key','Value');
var res = myMap.get('key');

console.log(var); // Result is: 'Value'
0

上一篇:

下一篇:

精彩评论

暂无评论...
验证码 换一张
取 消

最新问答

问答排行榜