Practice Time: List Filters

 

Practice Time

You can do the following filter exercise in REPL.

1. Create a list of spices, as follows:

val spices = listOf("curry", "pepper", "cayenne", "ginger", "red curry", "green curry", "red pepper" )

2. Create a filter that gets all the curries and sorts them by string length.
   • Hint: After you type the dot (.), IntelliJ will give you a list of functions you can apply.
3. Filter the list of spices to return all the spices that start with 'c' and end in 'e'. Do it in two different ways.
4. Take the first three elements of the list and return the ones that start with 'c'.

/** File:           Main.kt
 *  Programmer:      Nolverto Urias Obeso
 *  Creation Date:   06/13/2023
 *  Description:     Use the filters in a list
 */

fun main() {
    // 1. Create a list of spices
    val spices = listOf("curry", "pepper", "cayenne", "ginger", "red curry", "green curry", "red pepper" )

    // 2. Create a filter that gets all the curries and sorts them by string length
    println(spices.filter { it.contains("curry")}.sortedBy { it.length })

    // 3. Filter the list of spices to return all the spices that start with 'c' and end in 'e'.
    // Do it in three different ways.
    println(spices.filter { it[0] == 'c' && it[it.length-1]=='e' })
    println(spices.filter { it.startsWith('c')}.filter { it.endsWith('e')})
    println(spices.filter { it.startsWith('c') && it.endsWith('e')})

    // 4. Take the first three elements of the list and return the ones that start with 'c'.
    println(spices.take(3).filter { it.startsWith('c')})
}

Output:

[curry, red curry, green curry]
[cayenne]
[cayenne]
[cayenne]
[curry, cayenne]