我该如何用...来写斐波那契？

Question

**我该如何编写使用javascript中的for ... of产生Fibonacci的程序？

我已经尝试过了，效果很好

function createFibonacci(number) {
    var i;
    var fib = []; // Initialize array!

    fib[0] = 0;
    fib[1] = 1;
    for (i = 2; i <= number; i++) {
      // Next fibonacci number = previous + one before previous
      // Translated to JavaScript:
      fib[i] = fib[i - 2] + fib[i - 1];
      console.log(fib[i]);
    }
}

createFibonacci(8);

但是我想知道是否可以使用 for..of 编写它，有什么办法吗？

Answer 1

这里是一个选择，使用generator：

function createFibonacci(number) {
  // fibonacci generator
  const gen = (function *(i) {
    let a = 1, b = 1, c;
    if (i--) yield a;
    if (i--) yield b;
    while (i--) {
      yield c = a + b;
      [a, b] = [b, c];
    }
  });

  for (let f of gen(number)) {
    console.log(f);
  }
}

createFibonacci(8);

正如@T.J. Crowder所述，for...of循环仅用于消耗序列，该序列实际上是由生成器生成的。

Answer 2

您可以带发电机。

function* createFibonacci(number, a = 0, b = 1) {
    if (a === 0)
        if (number--) yield 1;
        else return;
    if (!number--) return
    yield a + b;
    yield* createFibonacci(number, b, a + b);
}

console.log(...createFibonacci(0));
console.log(...createFibonacci(1));
console.log(...createFibonacci(2));
console.log(...createFibonacci(3));
console.log(...createFibonacci(4));
console.log(...createFibonacci(5));
console.log(...createFibonacci(6));
console.log(...createFibonacci(7));
console.log(...createFibonacci(8));

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Rup稍有帮助的另一种方法。

function* createFibonacci(number, index = 1) {
    createFibonacci.values = createFibonacci.values || [0, 1];
    for (; index < createFibonacci.values.length && index < number + 1; ++index)
        yield createFibonacci.values[index];
    if (index >= number + 1) return;
    yield createFibonacci.values[index] = createFibonacci.values[index - 2] + createFibonacci.values[index - 1];
    yield* createFibonacci(number, index + 1);
}

console.log(...createFibonacci(0));
console.log(...createFibonacci(1));
console.log(...createFibonacci(2));
console.log(...createFibonacci(3));
console.log(...createFibonacci(4));
console.log(...createFibonacci(5));
console.log(...createFibonacci(6));
console.log(...createFibonacci(7));
console.log(...createFibonacci(8));

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