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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 JavaScript?
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JavaScript does not support associative arrays. You should use objects when you want the element names to be strings (text). You should use arrays when you want the element names to be numbers.
An associative array is declared or dynamically createdWe can create it by assigning a literal to a variable. var arr = { "one": 1, "two": 2, "three": 3 }; Unlike simple arrays, we use curly braces instead of square brackets. This has implicitly created a variable of type Object.
[] is declaring an array. {} is declaring an object. An array has all the features of an object with additional features (you can think of an array like a sub-class of an object) where additional methods and capabilities are added in the Array sub-class.
Associative arrays are basically objects in JavaScript where indexes are replaced by user defined keys. They do not have a length property like normal array and cannot be traversed using normal for loop. Following is the code for associative arrays in JavaScript −
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
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