Arrays with Loops
Explore how to use for and while loops to access and manipulate JavaScript arrays effectively. Understand array indexing, generate sequences like Fibonacci dynamically based on input, and practice writing programs that test palindromes, sort arrays, and verify Fibonacci sequences.
The for loop with arrays
The individual values in an array are accessed through an index number. The for loop variable can be used as an index number. However, the list values can also be used directly in the for loop.
The following program demonstrates the various ways of accessing array elements:
In the code above:
-
The new item is the
lengthfunction, which is used to get the length of the array. -
The first
forloop accesses the array values with the help of the loop variable,i. -
The second
forloop directly accesses the array values. -
The third
forloop accesses the list values with the help of the loop variablevand thelengthfunction.
The while loop with arrays
We usually use the while loop to deal with an array when the number of iterations is not fixed. For example, let’s say we want to generate n terms of a Fibonacci sequence and store them in a list, where n is the user input. A Fibonacci sequence is a sequence in which each number is the sum of the two preceding ones, except for the first two terms.
Let’s start by noting a few terms from this sequence: ...