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I need to get just the first item (actually, just the first key) off a rather large associative array in JavaScript. Here's how I'm doing it currently (using jQuery):
getKey = function (data) { var firstKey; $.each(data, function (key, val) { firstKey = key; return false; }); return firstKey; }; Just guessing, but I'd say there's got to be a better (read: more efficient) way of doing this. Any suggestions?
UPDATE: Thanks for the insightful answers and comments! I had forgotten my JavaScript 101, wherein the spec says you're not guaranteed a particular order in an associative array. It's interesting, though, that most browsers do implement it that way. I'd prefer not to sort the array before getting that first key, but it may be unavoidable given my use case.
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reset() gives you the first value of the array if you have an element inside the array: $value = reset($array); It also gives you FALSE in case the array is empty.
To get first element from array, use var first = array[0]; To get Name from it, use first.Name .
Now, if you need to move the last item to the first position, just use the return function array. pop() as input to the function array. unshift().
To get the first and last elements of an array, access the array at index 0 and the last index. For example, arr[0] returns the first element, whereas arr[arr. length - 1] returns the last element of the array.
You can avoid having to create a function by referencing the first entry returned from Object.keys():
var firstKey = Object.keys(data)[0]; For the first entry from a sorted key list, simply add a call to the .sort() method:
var firstKey = Object.keys(data).sort()[0]; If you love us? You can donate to us via Paypal or buy me a coffee so we can maintain and grow! Thank you!
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