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Retrieve only the queried element in an object array in MongoDB collection
...ction object field name represents the index of the field's first matching array element from the query. The following returns the same results as above:
db.test.find({"shapes.color": "red"}, {_id: 0, 'shapes.$': 1});
MongoDB 3.2 Update
Starting with the 3.2 release, you can use the new $filter...
Javascript Array of Functions
That does not work as intended because each function in the array is executed when the array is created.
18 Answers
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Convert Array to Object
... ['a','b','c']); // {0:"a", 1:"b", 2:"c"}
The own length property of the array is not copied because it isn't enumerable.
Also, you can use ES6 spread syntax to achieve the same result:
{ ...['a', 'b', 'c'] }
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How do you find the sum of all the numbers in an array in Java?
I'm having a problem finding the sum of all of the integers in an array in Java. I cannot find any useful method in the Math class for this.
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How do I iterate over an NSArray?
I'm looking for the standard idiom to iterate over an NSArray. My code needs to be suitable for OS X 10.4+.
8 Answers
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How to find index of list item in Swift?
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As swift is in some regards more functional than object-oriented (and Arrays are structs, not objects), use the function "find" to operate on the array, which returns an optional value, so be prepared to handle a nil value:
let arr:Array = ["a","b","c"]
find(arr, "c")! // 2
find(a...
Javascript - remove an array item by value [duplicate]
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You'll want to use JavaScript's Array splice method:
var tag_story = [1,3,56,6,8,90],
id_tag = 90,
position = tag_story.indexOf(id_tag);
if ( ~position ) tag_story.splice(position, 1);
P.S. For an explanation of that cool ~ tilde shortcut, see t...
How to check if a string array contains one string in JavaScript? [duplicate]
I have a string array and one string. I'd like to test this string against the array values and apply a condition the result - if the array contains the string do "A", else do "B".
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How to Update Multiple Array Elements in mongodb
I have a Mongo document which holds an array of elements.
15 Answers
15
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Count, size, length…too many choices in Ruby?
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For arrays and hashes size is an alias for length. They are synonyms and do exactly the same thing.
count is more versatile - it can take an element or predicate and count only those items that match.
> [1,2,3].count{|x| x &...