This answer details how to shuffle with a fast and uniform algorithm (Fisher-Yates) in Swift 4.2+ and how to add the same feature in the various previous versions of Swift. The naming and behavior for each Swift version matches the mutating and nonmutating sorting methods for that version. Swift 4.2+ shuffle and shuffled are native … Read more
You can use an object to hold the results: const arr = [5, 5, 5, 2, 2, 2, 2, 2, 9, 4]; const counts = {}; for (const num of arr) { counts[num] = counts[num] ? counts[num] + 1 : 1; } console.log(counts[5], counts[2], counts[9], counts[4]); So, now your counts object can tell you what … Read more
There are many ways to do this, one is reject noEmptyCities = cities.reject { |c| c.empty? } You can also use reject!, which will modify cities in place. It will either return cities as its return value if it rejected something, or nil if no rejections are made. That can be a gotcha if you’re … Read more
With ES6, we now have a simple way to create an Array from a NodeList: the Array.from() function. // nl is a NodeList let myArray = Array.from(nl)
I’m not sure about more efficient in terms of big-O but certainly using the unshift method is more concise: var a = [1, 2, 3, 4]; a.unshift(0); // => [0, 1, 2, 3, 4] console.log({a}); [Edit] This jsPerf benchmark shows that unshift is decently faster in at least a couple of browsers, regardless of possibly … Read more
Since the sort part is already answered. I’m just going to propose another elegant way to get the indexOf of a property in your array Your example is: var Data = [ {id_list:1, name:’Nick’, token:’312312′}, {id_list:2, name:’John’, token:’123123′} ] You can do: var index = Data.map(function(e) { return e.name; }).indexOf(‘Nick’); var Data = [{ id_list: … Read more
The var_dump function displays structured information about variables/expressions including its type and value. Arrays are explored recursively with values indented to show structure. It also shows which array values and object properties are references. The print_r() displays information about a variable in a way that’s readable by humans. array values will be presented in a … Read more
If you’re concatenating more than two arrays, concat() is the way to go for convenience and likely performance. var a = [1, 2], b = [“x”, “y”], c = [true, false]; var d = a.concat(b, c); console.log(d); // [1, 2, “x”, “y”, true, false]; For concatenating just two arrays, the fact that push accepts multiple … Read more
Take a look at Array.slice(begin, end) const ar = [1, 2, 3, 4, 5]; // slice from 1..3 – add 1 as the end index is not included const ar2 = ar.slice(1, 3 + 1); console.log(ar2);
var z = new int[x.Length + y.Length]; x.CopyTo(z, 0); y.CopyTo(z, x.Length);