android kotlin - How to partition a string

MainActivity.kt

package com.cfsuman.kotlintutorials

import android.os.Bundle
import android.text.method.ScrollingMovementMethod
import android.widget.TextView
import androidx.appcompat.app.AppCompatActivity


class MainActivity : AppCompatActivity() {
    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_main)

        // get the widgets reference from XML layout
        val textView = findViewById<TextView>(R.id.textView)

        // make textview content scrollable
        textView.movementMethod = ScrollingMovementMethod()


        val string = "This is A SAMple striNg."

        textView.text = string

        /*
            documentation source: kotlinlang.org
                Splits the original char sequence into pair of char sequences,
                where first char sequence contains characters for which
                predicate yielded true, while second char sequence
                contains characters for which predicate yielded false.
        */
        val result:Pair<String,String> = string.partition {
            it.isUpperCase()
        }

        textView.append("\n\n")
        textView.append("Uppercase characters....\n")
        textView.append(result.first)

        textView.append("\n\n")
        textView.append("Exclude uppercase characters....\n")
        textView.append(result.second)
    }
}
activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:background="#F8F8F8"
    android:padding="24dp">

    <TextView
        android:id="@+id/textView"
        android:layout_width="0dp"
        android:layout_height="0dp"
        android:fontFamily="sans-serif"
        android:textSize="24sp"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent" />

</androidx.constraintlayout.widget.ConstraintLayout>