Question

为什么此代码返回未定义我找不到原因

function findShort(s){
  let splitted = s.split(' ');
  let result = splitted[0].length ;
  let looped
  for (var i=0 ; i++ ; i<splitted.length){ 
    looped = splitted[i].length;
    if (looped < result) {return looped}else {return result }}
};
console.log(findShort("bitcoin take over the world maybe who knows perhaps"));

我应该得到最小的单词数

Answer 1

您的for循环condition和increment被颠倒了：

for (var i=0 ; i++ ; i<splitted.length){ ...

应该是：

for (var i = 0; i < splitted.length; i++) { ...

您还必须修复循环代码，因为它会在内部if语句的两个分支中返回，这意味着将仅运行一次迭代。

如果要返回最小单词的长度，请执行以下操作：

function findShort(s) {
  let splitted = s.split(' ');
  let result = splitted[0].length;
  for (let i = 0; i < splitted.length; i++) { 
    const looped = splitted[i].length;
    if (looped < result) {
      result = looped;
    }
  }
  return result;
};
console.log(findShort("bitcoin take over the world maybe who knows perhaps"));

或更短使用Array.prototype.reduce()：

function findShortest(s) {
  return s.split(/\s+/).reduce((out, x) => x.length < out ? x.length : out, s.length);
};
console.log(findShortest('bitcoin take over the world maybe who knows perhaps'));

Answer 2

您的for循环实现是错误的，应该是：

for (var i=0; i<splitted.length; i++)

Answer 3

condition和increment的顺序在您for loop中以及循环中的代码都是错误的，

只有在所有情况下都有return时，它才会检查第一个元素。

这是正确的

function findShort(s) {
	let splitted = s.split(' ');
	let result = splitted[0].length;
	let looped
	for (var i = 0; i < splitted.length; i++) {
		looped = splitted[i].length;
		if (looped < result) { result = looped }
	}
	return result;
};

console.log(findShort("bitcoin take over the world maybe who knows perhaps"));

为什么用for循环功能会得到未定义的结果？

3 个答案: