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Arrays

Arrays are a fundamental data structure in JavaScript used to store multiple values in a single variable. They can hold any type of data, including numbers, strings, objects, and even other arrays. Arrays are mutable, meaning you can change their contents by adding, removing, or updating elements.

Creating Arrays

  • Array Literal: The most common way to create an array is using array literals:
     const fruits = ['apple', 'banana', 'cherry'];
  • Array Constructor: You can also use the Array constructor, but it's generally less common for simple arrays:
    You can also use the Array constructor, but it's generally less common for simple arrays:

    • Accessing Elements

  • Indexing: Elements in an array are accessed using numerical indexes starting from zero. The first element has index 0, the second element has index 1, and so on. fruits[0] will access the value "apple" in the above example.
  • Out-of-Bounds Access: Trying to access elements beyond the array's length results in undefined.

    • Array Properties and Methods:

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  • Length: The length property of an array represents the number of elements it holds. It's a writable property, so you can modify the length to shorten the array (by setting a higher value won't add elements, just empty slots).
  • Common Methods: JavaScript provides various built-in methods for working with arrays. Here are some examples:

    • - push()

      Adds one or more elements to the end of the array and returns the new length.

    • - pop()

      Removes the last element from the array and returns it.

    • - shift()

      Removes the first element from the array and returns it.

    • - unshift()

      Adds one or more elements to the beginning of the array and returns the new length.

    • - slice()

      Extracts a section of the array and returns a new array.

    • - concat()

      Merges two or more arrays and returns a new array.

    • - indexOf()

      Searches the array for a specific element and returns its index or -1 if not found.

    • - forEach()

      Executes a provided function once for each array element.

    • - map()

      Creates a new array with the results of calling a function on every element in the array.

    • - filter()

      Creates a new array with elements that pass a test implemented by the provided function.
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