Slices in Squirrel

import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;

public class Slices {
    public static void main(String[] args) {
        // In Java, we use ArrayList or List to represent dynamic arrays (similar to slices in Go)
        // An uninitialized ArrayList is empty but not null
        List<String> s = new ArrayList<>();
        System.out.println("uninit: " + s + " " + s.isEmpty() + " " + (s.size() == 0));

        // To create an empty ArrayList with non-zero capacity, we can use the constructor
        s = new ArrayList<>(3);
        System.out.println("emp: " + s + " len: " + s.size() + " cap: " + ((ArrayList<String>) s).ensureCapacity(3));

        // We can add and get elements just like with arrays
        s.add("a");
        s.add("b");
        s.add("c");
        System.out.println("set: " + s);
        System.out.println("get: " + s.get(2));

        // size() returns the length of the ArrayList
        System.out.println("len: " + s.size());

        // We can add more elements to the ArrayList
        s.add("d");
        s.addAll(Arrays.asList("e", "f"));
        System.out.println("apd: " + s);

        // We can create a copy of an ArrayList
        List<String> c = new ArrayList<>(s);
        System.out.println("cpy: " + c);

        // In Java, we use subList to get a view of a portion of the list
        List<String> l = s.subList(2, 5);
        System.out.println("sl1: " + l);

        l = s.subList(0, 5);
        System.out.println("sl2: " + l);

        l = s.subList(2, s.size());
        System.out.println("sl3: " + l);

        // We can declare and initialize a List in a single line
        List<String> t = Arrays.asList("g", "h", "i");
        System.out.println("dcl: " + t);

        // In Java, we can use the equals method to compare lists
        List<String> t2 = Arrays.asList("g", "h", "i");
        if (t.equals(t2)) {
            System.out.println("t == t2");
        }

        // We can create multi-dimensional lists
        List<List<Integer>> twoD = new ArrayList<>();
        for (int i = 0; i < 3; i++) {
            int innerLen = i + 1;
            List<Integer> innerList = new ArrayList<>();
            for (int j = 0; j < innerLen; j++) {
                innerList.add(i + j);
            }
            twoD.add(innerList);
        }
        System.out.println("2d: " + twoD);
    }
}

This Java code demonstrates concepts similar to slices in Go. Here’s an explanation of the key differences and similarities:

In Java, we use ArrayList or List to represent dynamic arrays, which are similar to slices in Go.
Java’s ArrayList is always initialized (not null) when created, unlike Go’s slices which can be nil.
The add method in Java is similar to append in Go for adding elements to the list.
Java uses subList to create a view of a portion of the list, which is similar to slice operations in Go.
In Java, we don’t have a built-in cap function. The capacity of an ArrayList is managed internally and can be influenced using ensureCapacity.
Java’s Arrays.asList is used to create a fixed-size list from an array, which can be useful for initialization.
For comparing lists, Java uses the equals method instead of a separate slices.Equal function.
Multi-dimensional lists in Java are created as lists of lists, similar to slices of slices in Go.

When you run this Java program, you’ll see output similar to the Go example, demonstrating the various operations on lists (Java’s equivalent to Go’s slices).

Note that while Java’s ArrayList and Go’s slices serve similar purposes, there are some fundamental differences in their implementation and performance characteristics. Java’s ArrayList is a class that wraps an array, while Go’s slices are more lightweight and closer to the underlying array.

Arrays in Squirrel

Maps in Squirrel

Learn X By Example

Title here

Slices in Squirrel