上下文：一部电影列表

在本节中，我们将从一个示例程序开始，逐步对其进行改进，但不添加任何新的功能。这一重要的编程任务被称为 重构。

我们最初的程序涉及最近的蝙蝠侠系列电影。数据以对象数组的形式呈现，每个对象描述了一部电影。

1const movieList = [
2  {
3    title: "Batman",
4    year: 1989,
5    director: "Tim Burton",
6    imdbRating: 7.6
7  },
8  {
9    title: "Batman Returns",
10    year: 1992,
11    director: "Tim Burton",
12    imdbRating: 7.0
13  },
14  {
15    title: "Batman Forever",
16    year: 1995,
17    director: "Joel Schumacher",
18    imdbRating: 5.4
19  },
20  {
21    title: "Batman & Robin",
22    year: 1997,
23    director: "Joel Schumacher",
24    imdbRating: 3.7
25  },
26  {
27    title: "Batman Begins",
28    year: 2005,
29    director: "Christopher Nolan",
30    imdbRating: 8.3
31  },
32  {
33    title: "The Dark Knight",
34    year: 2008,
35    director: "Christopher Nolan",
36    imdbRating: 9.0
37  },
38  {
39    title: "The Dark Knight Rises",
40    year: 2012,
41    director: "Christopher Nolan",
42    imdbRating: 8.5
43  }
44];

以下是使用这些数据展示电影相关信息的完整程序。

1// 获取电影标题
2const titles = [];
3for (const movie of movieList) {
4  titles.push(movie.title);
5}
6console.log(titles);
7
8// 统计克里斯托弗·诺兰执导的电影数量
9const nolanMovieList = [];
10for (const movie of movieList) {
11  if (movie.director === "Christopher Nolan") {
12    nolanMovieList.push(movie);
13  }
14}
15console.log('列表中有 ' + nolanMovieList.length + ' 部克里斯托弗·诺兰执导的电影。');
16
17// 获取IMDB评分大于等于7.5的电影标题
18const bestTitles = [];
19for (const movie of movieList) {
20  if (movie.imdbRating >= 7.5) {
21    bestTitles.push(movie.title);
22  }
23}
24console.log(bestTitles);
25
26// 计算克里斯托弗·诺兰电影的平均评分
27let ratingSum = 0;
28let averageRating = 0;
29for (const movie of nolanMovieList) {
30  ratingSum += movie.imdbRating;
31}
32averageRating = ratingSum / nolanMovieList.length;
33console.log(averageRating);