Iterating Over Arrays

Often, you’ll want to process each element of an array. Flint supports two types of loops for working with arrays:

1. Index-Based Loops: Ideal for accessing and modifying elements at specific indices.
2. Enhanced For Loops: Useful for iterating over all elements with simpler syntax.

Using the Index-Based Loop

def main():
    // Initialize array of size 5 with values of 4
    arr := int[5](4);
    // Set each element to the double of the index
    for i := 0; i < 5; i++:
        arr[i] = i * 2;
    print($"arr[3]: {arr[3]}"); // prints 'arr[3]: 6'

Using the Enhanced For Loop

In enhanced for loops, you can access both the index (i) and the element (elem), as learned in chapter 4:

def main():
    int[] arr = int[5](6); // Initialize array
    for i, elem in arr:
        print($"Index: {i}, Value: {elem}");

Output:

Index: 0, Value: 6
Index: 1, Value: 6
Index: 2, Value: 6
Index: 3, Value: 6
Index: 4, Value: 6

Iterables in Flint

Flint arrays are iterable, meaning they can be used in enhanced for loops. Other iterables include ranges, which we’ll discuss later. Remember: the choice of loop depends on whether you need access to indices (i) or also elements (elem).

Hint: The type of the indices (i) is always of type uint (no signed int values) and the type of the elements (elem) is always the type of the array elements. If you create a str array (str[]), for example, elem will be of type str.