如何打印出过滤的元素？

Question

How do I print out the filtered elements from the array?
I tried console.log('randomNumbers/smallNumbers');
But they didn't work.
Please advise, much thanks!

const randomNumbers = [375, 200, 3.14, 7, 13, 852];

const smallNumbers = randomNumbers.filter(num => {
  return num < 250;
});

Answer 1

It's not the logging you have troubles with - but Array.filter function. You seem to think it somehow consumes the whole array at once, hence attempt to use length and name the argument the same way as the original array.

What happens instead is that the function you pass in randomNumbers.filter (as its parameter) is called once per each element of that array, taking this element as its first argument.

If result of the function's call for this element is truthy, the element will stay in the result of .filter . If falsy, it gets discarded.

So it can written as simple as this:

 const randomNumbers = [375, 200, 3.14, 7, 13, 852]; const smallNumbers = randomNumbers.filter(number => number < 250); // log the resulting array console.log(smallNumbers); // log the small numbers' ratio console.log((smallNumbers.length / randomNumbers.length).toFixed(2));

Answer 2

const randomNumbers = [375, 200, 3.14, 7, 13, 852];
const smallNumbers = randomNumbers.filter(number => number < 250);

// log the resulting array
console.log(smallNumbers); 

// log the small numbers' ratio
console.log((smallNumbers.length / randomNumbers.length).toFixed(2));