Question

How to convert following multidimensional array to single dimensional associative array with minimum loop in jQuery?

array(array('a'=>3),array('b'=>2),array('c'=>4),array('d'=>3))

Expected result:

array('a'=>3,'b'=>2,'c'=>4,'d'=>3);

Answer 1

{'a':3, 'b':2, 'c':4, 'd':3}

…is the JS syntax you’re looking for in your result. JS doesn’t have associative arrays in the sense that, say, PHP does: it has objects, which do (approximately) the same job.

If the code you show is valid in some other language (PHP?), it could be converted to a JSON string and when the JSON is parsed by JS you’d end up with a JS array of objects as follows:

[ {'a':3}, {'b':2}, {'c':4}, {'d':3} ]

To convert that to a JS object rather than an array of objects the simplest way is probably to make use of jQuery.extend():

// assume some JSON.parse() or other process has created
myArr = [ {'a':3}, {'b':2}, {'c':4}, {'d':3} ]
// then

var tmpArr = myArr.slice(0);   // make shallow copy of myArr
tmpArr.unshift({});            // insert an empty object

var newObj = jQuery.extend.apply(this, tmpArr);

Demo: http://jsfiddle.net/SqcEw/

Note that if more than one of the elements in the original array had the same property name one would clobber the other in the final object.

Further reading:

• Working with objects (page has some load errors at the moment, but normally this is a good reference and I’m sure MDN will fix it soon)
• $.extend()