Remove lines from a file: Difference between revisions
Added Kotlin
(→{{header|UNIX Shell}}: add non-GNU sed option) |
(Added Kotlin) |
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=={{header|Kotlin}}==
<lang scala>// version 1.1.1
import java.io.File
fun removeLines(fileName: String, startLine: Int, numLines: Int) {
require(!fileName.isEmpty() && startLine >= 1 && numLines >= 1)
val f = File(fileName)
if (!f.exists()) {
println("$fileName does not exist")
return
}
var lines = f.readLines()
val size = lines.size
if (startLine > size) {
println("The starting line is beyond the length of the file")
return
}
var n = numLines
if (startLine + numLines - 1 > size) {
println("Attempting to remove some lines which are beyond the end of the file")
n = size - startLine + 1
}
lines = lines.take(startLine - 1) + lines.drop(startLine + n - 1)
val text = lines.joinToString(System.lineSeparator())
f.writeText(text)
}
fun printFile(fileName: String, message: String) {
require(!fileName.isEmpty())
val f = File(fileName)
if (!f.exists()) {
println("$fileName does not exist")
return
}
println("\nContents of $fileName $message:\n")
f.forEachLine { println(it) }
}
fun main(args: Array<String>) {
printFile("input.txt", "before removal")
removeLines("input.txt", 2, 3)
printFile("input.txt", "after removal of 3 lines starting from the second")
}</lang>
{{out}}
<pre>
Contents of input.txt before removal:
Line 1
Line 2
Line 3
Line 4
Line 5
Line 6
Line 7
Line 8
Contents of input.txt after removal of 3 lines starting from the second:
Line 1
Line 5
Line 6
Line 7
Line 8
</pre>
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