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A JavaScript array is a list-like object. You can use arrays to store any kind of data in a sequence, like a list.
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Arrays are one of the most useful data
types you have as a JavaScript developer.
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Arrays are the best way to group
similar data together in a sequence,
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such as a list of customers,
photos, dates, or
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even coordinates indicating
a precise spot on a screen.
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To use arrays effectively,
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you need a way of looking through
them to see the data they hold.
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This action of looking through
arrays is called iteration, and
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JavaScript provides many methods for
iterating over an array.
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For example, you might wanna
transform an array's elements, say,
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from strings to numbers.
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Or you might want to add an array
of numbers and return the sum.
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Maybe you have an array of dates and
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you want to remove all dates before,
say, July 1st.
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In this course,
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I'll show you how to use array methods
to accomplish these kinds of tasks.
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You'll also practice
iterating over arrays so
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you can retain the knowledge
you'll build here.
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Before diving in though, let's take
a moment to review what arrays are.
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An array is a sequenced selection of data,
basically a list of information.
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In fact, arrays are sometimes referred
to as list like objects in JavaScript.
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Think of a list on a piece of paper,
like a shopping list for example.
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A shopping list is a group
of items you need to buy.
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Those items appear in specific order,
starting at the top and going down.
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So when you want to add something to
the list, you write it at the bottom.
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JavaScript arrays have
similar characteristics.
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You can store and position data
inside them as you can with a list.
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To add data to an array, you typically
write it in using a push method for
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example.
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Storing anything whether
it is a name on a list or
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an item in an array is useless
unless you can find it again later.
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To find a list item, you'll typically
start reading at the top and
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go down till you see what you're after.
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You can look through arrays in
a similar manner, but with arrays,
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this process is called iteration.
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And unlike a shopping list,
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which is really a collection of strings,
the names of each item you want to buy,
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you can store any JavaScript data
type as an item in an array.
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A string, a number, an object,
and even another array.
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JavaScript uses integers called
indices to identify the position
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of an item in an array.
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The first item in an array is that index
0, the next item is at 1 and so on.
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This means if you know the location
of an item in an array,
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you can access it directly with its index.
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Put the index and
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square brackets after the array to
access a specific piece of data.
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In the next video, we'll compare
two way to iterate over an array.
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A for loop, and an array method called for
each, I'll see you there.
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