- Added new function in org.jetbrains.kotlinx.dataframe.samples.api.Write for keepFile functionality

 - Added example of keepFile use in writeExcel to write.md

Signed-off-by: LeandroC89 <[email protected]>

Author: LeandroC89

docs/StardustDocs/topics/write.md

@@ -116,3 +116,18 @@ wb.close()
 ```
 
 <!---END-->
+
+Add new sheets without using Apache POI directly by using a parameter to keep using the same file if it already exists
+
+<!---FUN writeXlsWithMultipleSheets-->
+
+```kotlin
+// Create a new Excel workbook with a single sheet called "allPersons", replacing the file if it already exists -> Current sheets: allPersons
+val allPersonsSheet = df.writeExcel(file, sheetName = "allPersons")
+// Add a new sheet to the previous file without replacing it, by setting keepFile = true -> Current sheets: allPersons, happyPersons
+val happyPersonsSheet = df.filter { person -> person.isHappy }.remove("isHappy").writeExcel(file, sheetName = "happyPersons", keepFile = true)
+// Add a new sheet to the previous file without replacing it, by setting keepFile = true -> Current sheets: allPersons, happyPersons, unhappyPersons
+val unhappyPersonsSheet = df.filter { person -> !person.isHappy }.remove("isHappy").writeExcel(file, sheetName = "unhappyPersons", keepFile = true)
+```
+
+<!---END-->

tests/src/test/kotlin/org/jetbrains/kotlinx/dataframe/samples/api/Write.kt

@@ -121,6 +121,20 @@ class Write : TestBase() {
         }
     }
 
+    @Test
+    fun writeXlsWithMultipleSheets() {
+        useTempFile { file ->
+            // SampleStart
+            // Create a new Excel workbook with a single sheet called "allPersons", replacing the file if it already exists -> Current sheets: allPersons
+            val allPersonsSheet = df.writeExcel(file, sheetName = "allPersons")
+            // Add a new sheet to the previous file without replacing it, by setting keepFile = true -> Current sheets: allPersons, happyPersons
+            val happyPersonsSheet = df.filter { person -> person.isHappy }.remove("isHappy").writeExcel(file, sheetName = "happyPersons", keepFile = true)
+            // Add a new sheet to the previous file without replacing it, by setting keepFile = true -> Current sheets: allPersons, happyPersons, unhappyPersons
+            val unhappyPersonsSheet = df.filter { person -> !person.isHappy }.remove("isHappy").writeExcel(file, sheetName = "unhappyPersons", keepFile = true)
+            // SampleEnd
+        }
+    }
+
     companion object {
         private fun String.rejoinWithSystemLineSeparator() = rejoinWithLineSeparator(System.lineSeparator())