Square an arraylist (new to coding)

Processing Coding Questions
1

Hello guys how do i square all the numbers in an arrayList?
i want to square each number with itself, is this possible?

2

https://processing.org/reference/sq_.html

please show your code with the loop over the arrayList

3

Welcome to the forum!

Yes, you for loop over the arraylist and use get and set command - see the reference for Arraylist

4

Docs.Oracle.com/en/java/javase/11/docs/api/java.base/java/util/List.html#replaceAll(java.util.function.UnaryOperator)

Docs.Oracle.com/en/java/javase/11/docs/api/java.base/java/util/function/UnaryOperator.html

// https://Discourse.Processing.org/t/square-an-arraylist-new-to-coding/15489/4
// GoToLoop (2019/Nov/14)

import java.util.List;
import java.util.function.UnaryOperator;

static final UnaryOperator<Float> SQ_FLOAT = new UnaryOperator<Float>() {
  @Override final Float apply(final Float n) {
    return sq(n);
  }
};

static final List<Float> sqList(final List<Float> list) {
  list.replaceAll(SQ_FLOAT);
  return list;
}

final List<Float> floats = new ArrayList<Float>();

void setup() {
  floats.add(PI);
  floats.add(TAU);
  floats.add(EPSILON);

  println(floats);         // [3.1415927, 6.2831855, 1.0E-4]
  println(sqList(floats)); // [9.869605, 39.47842, 9.999999E-9]

  exit();
}
5

Docs.Oracle.com/en/java/javase/11/docs/api/java.base/java/util/List.html#listIterator()

Docs.Oracle.com/en/java/javase/11/docs/api/java.base/java/util/ListIterator.html#set(E)

// https://Discourse.Processing.org/t/square-an-arraylist-new-to-coding/15489/5
// GoToLoop (2019/Nov/14)

import java.util.List;
import java.util.ListIterator;

static final List<Float> sqList(final List<Float> list) {
  for (final ListIterator<Float> iter = list.listIterator(); iter.hasNext(); )
    iter.set(sq(iter.next()));
  return list;
}

final List<Float> floats = new ArrayList<Float>();

void setup() {
  floats.add(PI);
  floats.add(TAU);
  floats.add(EPSILON);

  println(floats);         // [3.1415927, 6.2831855, 1.0E-4]
  println(sqList(floats)); // [9.869605, 39.47842, 9.999999E-9]

  exit();
}
6

Docs.Oracle.com/en/java/javase/11/docs/api/java.base/java/util/List.html#set(int,E)

// https://Discourse.Processing.org/t/square-an-arraylist-new-to-coding/15489/6
// GoToLoop (2019/Nov/14)

import java.util.List;

static final List<Float> sqList(final List<Float> list) {
  for (int i = 0, len = list.size(); i < len; ++i)  list.set(i, sq(list.get(i)));
  return list;
}

final List<Float> floats = new ArrayList<Float>();

void setup() {
  floats.add(PI);
  floats.add(TAU);
  floats.add(EPSILON);

  println(floats);         // [3.1415927, 6.2831855, 1.0E-4]
  println(sqList(floats)); // [9.869605, 39.47842, 9.999999E-9]

  exit();
}
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