In general, all 6 fold functions apply a binary operator to each element of a collection. The result of each step is passed on to the next step (as input to one of the binary operator’s two arguments). This way we can cumulate a result. reduceLeft and reduceRight cumulate a single result. foldLeft and foldRight … Read more
A short-hand way to do it is to convert it to an array via the ES6 spread operator. Then all the array functions are available to you. const mySet = new Set([1,2,3,4]); […mySet].reduce(…);
It was moved to functools.
One option would be to reduce the keys(): var o = { a: {value:1}, b: {value:2}, c: {value:3} }; Object.keys(o).reduce(function (previous, key) { return previous + o[key].value; }, 0); With this, you’ll want to specify an initial value or the 1st round will be ‘a’ + 2. If you want the result as an Object … Read more
A cleaner way to accomplish this is by providing an initial value as the second argument to reduce: var arr = [{x:1}, {x:2}, {x:4}]; var result = arr.reduce(function (acc, obj) { return acc + obj.x; }, 0); console.log(result); // 7 The first time the anonymous function is called, it gets called with (0, {x: 1}) … Read more
You can read about the changes in What’s New In Python 3.0. You should read it thoroughly when you move from 2.x to 3.x since a lot has been changed. The whole answer here are quotes from the documentation. Views And Iterators Instead Of Lists Some well-known APIs no longer return lists: […] map() and … Read more
For Python 3.8+, use statistics.fmean for numerical stability with floats. (Fast.) For Python 3.4+, use statistics.mean for numerical stability with floats. (Slower.) xs = [15, 18, 2, 36, 12, 78, 5, 6, 9] import statistics statistics.mean(xs) # = 20.11111111111111 For older versions of Python 3, use sum(xs) / len(xs) For Python 2, convert len to … Read more