Late one, but I don’t know why nobody suggests something much simpler: listOfTags.filter((tag, index, array) => array.findIndex(t => t.color == tag.color && t.label == tag.label) == index);
The exception is correct, reduce does not work on an empty iterable or array. What you’re probably looking for is fold, which takes a starting value and an operation which is applied successively for each element of the iterable. reduce takes the first element as a starting value, so it needs no additional value to … Read more
In ES6 you can use spread operator. One string solution: Math.min(…items)
x has a shape of (2, 3) (two rows and three columns): 1 1 1 1 1 1 By doing tf.reduce_sum(x, 0) the tensor is reduced along the first dimension (rows), so the result is [1, 1, 1] + [1, 1, 1] = [2, 2, 2]. By doing tf.reduce_sum(x, 1) the tensor is reduced along … Read more
Python 3.x does have reduce, you just have to do a from functools import reduce. It also has “dict comprehensions”, which have exactly the syntax in your example. Python 2.7 and 3.x also have a Counter class which does exactly what you want: from collections import Counter cnt = Counter(“abracadabra”) In Python 2.6 or earlier, … Read more
The method fold (originally added for parallel computation) is less powerful than foldLeft in terms of types it can be applied to. Its signature is: def fold[A1 >: A](z: A1)(op: (A1, A1) => A1): A1 This means that the type over which the folding is done has to be a supertype of the collection element … Read more
When you try to do return filteredArr.push(collectionElement), in essence you are returning length of filteredArr after the push operation. The push() method adds one or more elements to the end of an array and returns the new length of the array. Ref: Array.prototype.push(). You need to return the filteredArr from your anonymous function, so that … Read more
I believe this is because the type for [] is inferred to be never[], which is the type for an array that MUST be empty. You can use a type cast to address this: [‘a’, ‘b’, ‘c’].reduce((accumulator, value) => accumulator.concat(value), [] as string[]); Normally this wouldn’t be much of a problem since TypeScript does a … Read more
push returns the new length of the array. What you need is the initially provided array. So change the code as below. var store = [0, 1, 2, 3, 4]; var stored = store.reduce(function(pV, cV, cI){ console.log(“pv: “, pV); pV.push(cV); return pV; // ********* Important ****** }, []); concat returns the new array combining the … Read more
The reduce phase has 3 steps: shuffle, sort, reduce. Shuffle is where the data is collected by the reducer from each mapper. This can happen while mappers are generating data since it is only a data transfer. On the other hand, sort and reduce can only start once all the mappers are done. You can … Read more