Basic comprehensions in Groovy

comprehension.groovy

// Some things
List<String> items = ["banana", "pear", "apple"]

// Filtering out
List<String> e_items = items.findAll { it.contains("e") }
println(e_items)

// List from list
List<String> fruity = items.collect { "Fruit: $it" }
println fruity

// Map from list
Map<String,int> counted = items.collectEntries { ["$it", it.length() ] }
println counted

// List from map
List<int> lengths = counted.collect { it.value }
println lengths

Install Groovy on Ubuntu 22.04 :

sudo apt update && sudo apt install openjdk-11-jdk -y && sudo snap install --classic groovy -y