首先让我们来看下上面的注释: Performs a reduction on the elements of this stream, using the provided identity, accumulation and combining functions.使用提供的初始值、accumulation、combining对流执行reduction操作。等价于下面这个函数This is equivalent to:U result = identity;for (T element : this stream)...
console.log(myArrayWithNoDuplicates) Copy to Clipboard 使用.reduce() 替换 .filter().map() 使用Array.filter()和Array.map()会遍历数组两次,而使用具有相同效果的Array.reduce()只需要遍历一次,这样做更加高效。(如果你喜欢for循环,你可用使用Array.forEach()以在一次遍历中实现过滤和映射数组) 1 2 3 4 ...
// friends - an array of objects // where object field "books" - list of favorite books var friends = [ { name: "Anna", books: ["Bible", "Harry Potter"], age: 21, }, { name: "Bob", books: ["War and peace", "Romeo and Juliet"], age: 26, }, { name: "Alice", books...
function ab(data, resultArray) { return data.reduce((pre, cur) => { let tempArray = [...resultArray]; let temp = { ...cur }; // delete temp.children tempArray.push(temp.value); return cur.children && cur.children.length > 0 ? { ...pre, ...ab(cur.children, tempArray) }...
}//3. If len is 0 and initialValue is not present,//throw a TypeError exception.if(k >= len) {//如果数组长度为0且没有指定initialValue抛错误thrownewTypeError( 'Reduce of empty array ' + 'with no initial value'); } value= o[k++];//否则累加器第一个值等于array[0]}//8. Repeat,...
关于减速机的更多信息:https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/Reduce 我认为关键是要把你的头绕在initialValue和accumulator上,以及当涉及到Array.reduce()时它与currentValue的关系 我已经编写了以下代码: const car = [ { "name": "available", "Vehciles": ...
reduce() 方法对数组中的每个元素按序执行一个提供的 reducer 函数,每一次运行 reducer 会将先前元素的计算结果作为参数传入,最后将其结果汇总为单个返回值。
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一,将所有值相加 二,自定义函数,使相乘 三,改进代码,将自定义函数删除,改用匿名函数 print(reduce_test(lambda x,y:x*y,num_1)) 四,优化代码,将res=1替换为: res=array.pop(0) 五,指定一个初始值(将初始值与列表中所有元素相乘) reduce函数合并一个完整的序列,压缩,得到最终结果。 map函数是在原列表...
System.out.printf("The number of values: %d%n", n); } We have an array of integers. We create a stream from the array withArrays.streamand perform two reductions:sumandcount. The sum of values: 72 The number of values: 8 Java reduce Optional ...