For example, the other day there was a PR for creating a simple csv report and they wrote something like
val buffer = new StringBuffer()
buffer.add(header)
buffer.add("\n")
someList.forEach { item =>
val values: List[String] = someTransformation(item)
buffer.add(values.mkString(","))
buffer.add("\n")
}
buffer.toString
val rows: List[String] = someList.map { item =>
val values: List[String] = someTransformation(item)
values.mkString(",")
}
(header :: rows).mkString("\n") + "\n" // I forgot whether they appended the string with a line break or not...I actually also find it more readable, but that’s a personal preference
1) is more readable (fight me)
2) doesn't rely on internal optimizations for string concatenation, in order to be as efficient
3) doesn't create extra garbage (linked lists)
In fact, the only thing I would change is make it a for loop instead.
(header :: rows).mkString("", "\n", "\n")