我试着在spark中运行一些scala代码，下面是一个在线视频教程：它是一个wordcount程序

val lines = sc.textFile("/data/mr/wordcount/big.txt")
val words = lines.flatMap(x => x.split(" "))
val pairs = words.map(s => (s.toLowerCase(), 1))
val counts = pairs.reduceByKey((a, b) => a + b)
counts.take(10)

<console>:24: error: not found: value counts
   counts.take(10)
   ^

每当我运行不以val开头的ever命令时，都会出现相同的错误