How to do associative array/hashing in JavaScript
I want to calculate/store some statistics information using JavaScript, the equivalent code in C# is below (features I need are -- key-value pair, string/int key value pair, manipulate values by keys, etc.), any ideas how to implement the same function in JavaScript? Looks like there is no built-in Dictionary or Hashtable?
Dictionary<string, int> statistics;
statistics["Foo"] = 10;
statistics["Goo"] = statistics["Goo"] + 1;
statistics.Add("Zoo", 1);
Use JavaScript objects as associative arrays.
Associative Array: In simple words associative arrays use Strings instead of Integer numbers as index.
Create an object with
var dictionary = {};
Javascript allows you to add properties to objects by using the following syntax:
Object.yourProperty = value;
An alternate syntax for the same is:
Object["yourProperty"] = value;
If you can also create key to value object maps with the following syntax
var point = { x:3, y:2 };
point["x"] // returns 3
point.y // returns 2
You can iterate through an associative array using the for..in loop construct as follows
for(var key in dict){
var value = dict[key];
/* use key/value for intended purpose */
}
var associativeArray = {};
associativeArray["one"] = "First";
associativeArray["two"] = "Second";
associativeArray["three"] = "Third";
如果您来自面向对象的语言，您应该阅读本文。
Unless you have a specific reason not to, just use a normal object. Object properties in Javascript can be referenced using hashtable-style syntax:
var hashtable = {};
hashtable.foo = "bar";
hashtable['bar'] = "foo";
Both foo and bar elements can now then be referenced as:
hashtable['foo'];
hashtable['bar'];
// or
hashtable.foo;
hashtable.bar;
Of course this does mean your keys have to be strings. If they're not strings they are converted internally to strings, so it may still work, YMMV.
链接地址: http://www.djcxy.com/p/91912.html