包含 javascript 中的枚举等价物的列表理解

Question

请问这个python代码javascript中的等价物是什么

guessed_index = [
        i for i, letter in enumerate(self.chosen_word)
        if letter == self.guess
    ]

ES6 等价物中不存在枚举和列表理解，我如何将这两种想法合二为一

Answer 1

也许findIndex有用？

const word = "Hello";
const guess = "o";
const guessed_index = [...word].findIndex(letter => letter === guess);
console.log(guessed_index)

Answer 2

关注问题的可迭代/enumerate 部分，而不是您正在执行的特定任务：您可以实现 Python's enumerate using a generator function 的 JavaScript 类似物，并使用结果通过 for-of 生成器（它是可迭代对象的超集）（如果您愿意，也可以手动生成）：

function* enumerate(it, start = 0) {
    let index = start;
    for (const value of it) {
        yield [value, index++];
    }
}

const word = "hello";
const guess = "l";
const guessed_indexes = [];
for (const [value, index] of enumerate(word)) {
    if (value === guess) {
        guessed_indexes.push(index);
    }
}
console.log(`guessed_indexes for '${guess}' in '${word}':`, guessed_indexes);

或者您可以编写一个特定的生成器函数来执行查找匹配项的任务：

function* matchingIndexes(word, guess) {
    let index = 0;
    for (const letter of word) {
        if (letter === guess) {
            yield index;
        }
        ++index;
    }
}

const word = "hello";
const guess = "l";
const guessed_indexes = [...matchingIndexes(word, guess)];

console.log(`guessed_indexes for '${guess}' in '${word}':`, guessed_indexes);

Answer 3

为了不精通 python 的潜在读者清楚起见，下面是相当于您的理解的 python 循环：

guessed_index = []
i = 0
for letter in self.chosen_word:
    if letter == self.guess:
        guessed_index.append(i)
    i += 1

包含 javascript 中的枚举等价物的列表理解

list comprehension containing enumerate equivalent in javascript

javascript

python

list-comprehension

enumerate