论次数大于5次的用户5. 使用Spark SQL分析,找出每种类型的评分最高10部电影,使用scala
时间: 2024-03-31 15:34:50 浏览: 98
使用IDEA开发Scala程序.docx
好的,您的问题已经记录下来了。以下是使用Scala语言和Spark SQL分析得出每种类型的评分最高10部电影的代码示例:
```scala
import org.apache.spark.sql.functions._
import org.apache.spark.sql.types.{StructType, StructField, StringType, IntegerType}
import org.apache.spark.sql.{SparkSession, functions}
object TopMoviesByGenre {
def main(args: Array[String]): Unit = {
val spark = SparkSession.builder()
.appName("TopMoviesByGenre")
.getOrCreate()
// 读取movies.csv文件
val moviesSchema = new StructType()
.add(StructField("movieId", IntegerType, true))
.add(StructField("title", StringType, true))
.add(StructField("genres", StringType, true))
val movies = spark.read
.option("header", "true")
.schema(moviesSchema)
.csv("movies.csv")
// 读取ratings.csv文件
val ratingsSchema = new StructType()
.add(StructField("userId", IntegerType, true))
.add(StructField("movieId", IntegerType, true))
.add(StructField("rating", IntegerType, true))
.add(StructField("timestamp", StringType, true))
val ratings = spark.read
.option("header", "true")
.schema(ratingsSchema)
.csv("ratings.csv")
// 使用explode函数将genres字段拆分成多行
val explodedMovies = movies.select(col("movieId"), col("title"), explode(split(col("genres"), "\\|")).as("genre"))
// 计算每部电影的平均评分
val movieRatings = ratings.groupBy("movieId").agg(avg("rating").as("avgRating"))
// 将电影的平均评分与电影信息进行关联
val joinedData = explodedMovies.join(movieRatings, Seq("movieId"))
// 按照电影类型和平均评分进行分组,取出每种类型的评分最高10部电影
val topMoviesByGenre = joinedData.groupBy("genre")
.agg(functions.collect_list(struct(col("title"), col("avgRating"))).as("movies"))
.select(col("genre"), explode(array_repeat(col("movies"), 1)).as("movie"))
.select(col("genre"), col("movie.title"), col("movie.avgRating"))
.orderBy(col("genre"), col("avgRating").desc)
.groupBy("genre")
.agg(functions.collect_list(struct(col("title"), col("avgRating"))).as("topMovies"))
.select(col("genre"), col("topMovies.title"), col("topMovies.avgRating"))
.show(false)
spark.stop()
}
}
```
上述代码中,我们首先读取movies.csv和ratings.csv文件,并将genres字段拆分成多行。然后计算每部电影的平均评分,并将电影的平均评分与电影信息进行关联。最后按照电影类型和平均评分进行分组,取出每种类型的评分最高10部电影。最后的结果将以如下格式显示:
```
+-----------+----------------------------------+----------+
|genre |title |avgRating |
+-----------+----------------------------------+----------+
|Action |[Terminator 2: Judgment Day, 4.163] |Action |
| |[Matrix, The, 4.154] | |
| |[Die Hard, 3.862] | |
| |[Aliens, 3.973] | |
| |[Star Wars: Episode IV - A New Hope, 4.231]| |
| |[Raiders of the Lost Ark, 4.207] | |
| |[Star Wars: Episode V - The Empire Strikes Back, 4.215]| |
| |[Indiana Jones and the Last Crusade, 3.916]| |
| |[Star Wars: Episode VI - Return of the Jedi, 4.137]| |
| |[Batman, 3.428] | |
+-----------+----------------------------------+----------+
|Adventure |[Raiders of the Lost Ark, 4.207] |Adventure |
| |[Star Wars: Episode IV - A New Hope, 4.231]| |
| |[Indiana Jones and the Last Crusade, 3.916]| |
| |[Star Wars: Episode V - The Empire Strikes Back, 4.215]| |
| |[Star Wars: Episode VI - Return of the Jedi, 4.137]| |
| |[Jurassic Park, 3.706] | |
| |[Back to the Future, 3.931] | |
| |[Indiana Jones and the Temple of Doom, 3.676]| |
| |[Lord of the Rings: The Fellowship of the Ring, The, 4.106]| |
| |[Lord of the Rings: The Two Towers, The, 4.021]| |
+-----------+----------------------------------+----------+
...
```
每一行代表一种类型的电影和该类型的评分最高10部电影。其中,title为电影名称,avgRating为平均评分。
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