遍历通过参数指定的行

Question

下面有一段代码从 s3 中的文件读取并处理所有行。该文件中没有任何行号。但是，我希望代码只处理特定的文件行。我应该如何处理？注意：起始行号和结束行号作为参数传递。下面是当前代码

var counter=0
s3Service.getS3FileBufferedReader(s3File).use { s3BufferedReader ->

            s3BufferedReader.useLines { lines ->

                lines.forEach {
                    // Process each line


                    val transaction = Transaction(it)

                    // does some processing 

                    counter ++
                    log.info("Line number: ${counter}")
                }
            }
        }```

What I'm trying to achieve is, instead of processing the whole file, I want to process lines from 10 to 20. The catch is, the file only has data and no line numbers in it.

Answer 1

您可以为此使用 Sequence#drop(Int) 和 Sequence#take(Int)：

lines.drop(start - 1).take(end - start + 1).forEach {
    // do your stuff with the line
}

遍历通过参数指定的行

loop through the lines which are specified through a parameter

java

loops

filereader

file-processing

kotlin