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RUBY - ARRAYS

An Array in Ruby is a Collection that holds multiple values, of different Data Types. And in an Array the elements are ordered (We will explain it soon), the values are changeable and allows duplicate values.

There are two ways by which you can declare an Array.

You can place multiple values inside square brackets [] and Ruby will understand that it is a Array.
```
x = [5, "John", "Ruby"]
```

You can use the new method on Array class and specify the size of the Array.
```
arr = Array.new(10)
```

Let us see the first way of creating Array, i.e. Using square brackets [].

Creating a 'Array' with values of different Data Types

Example :

x = [5, "John", "Ruby"]
puts x

Output :

5
John
Ruby

So, in the above code we have created a Array using square brackets [].

And put an Integer type value (i.e. 5) and two String type value (i.e. John and Ruby)

x = [5, "John", "Ruby"]

And initialised to the variable x.

So, we can see that two different data types are assigned to a Array.

In the next line we have printed the Array using the puts statement.

puts x

Now, if we see the output,

Output :

5
John
Ruby

Iterating a Array using for loop

Example :

x = [5, "John", "Ruby"]
for i in x
	puts i
end

Output :

5
John
Ruby

Similarly, in the above code we have created a Array using square brackets [].

x = [5, "John", "Ruby"]

And initialised to the variable x.

In the next line we have used the for loop to Iterate through the Array.

for i in x
	puts i
end

Now, if we see the iterations of for loop,

for i in x

1st Iteration

In the first Iteration the first value of the Array x (i.e. 5) is taken and put into the variable i.

And the print statement, prints the value of i.

Output :

2nd Iteration

Similarly, in the second Iteration the second value of the Array x (i.e. John) is taken and put into the variable i.

And the print statement, prints the value of i.

Output :

5
John

3rd Iteration

Similarly, in the third Iteration the third value of the Array x (i.e. Ruby) is taken and put into the variable i.

And the print statement, prints the value of i.

Output :

5
John
Ruby

Now, if you see the final output. You can find that the values of the Array are displayed in the same way they were inserted.

i.e. First 5 is printed, then the name John and finally Ruby is printed.

And if you see the Array,

x = [5, "John", "Ruby"]

It is printed in the same order it was inserted. And this is why a Array is said to be Ordered.

Let us see the second way of creating an Array. i.e. Using the new method.

Creating a 'Array' with new

So far we have seen variables, which is used to store a single value. But what if we need to store 100 values?

We cannot create 100 variables. And to fill this gap Arrays came into picture.

Arrays are used to store multiple values of the same or different type.

Below is the way of declaring an array of size 10:

arr = Array.new(100)

Now, we will be asking Ruby to store numbers 1 to 10 in an array.

Example :

arr = Array.new(10)

for i in 0..9
	arr[i] = i + 1
end	
for i in 0..9
	puts "The contents of the array are : #{arr[i]}"
end

Output :

The contents of the array are : 1
The contents of the array are : 2
The contents of the array are : 3
The contents of the array are : 4
The contents of the array are : 5
The contents of the array are : 6
The contents of the array are : 7
The contents of the array are : 8
The contents of the array are : 9
The contents of the array are : 10

So, in the above code, we have declared an Array to hold 10 numbers.

arr = Array.new(10)

And used the for loop to store the numbers 1 to 10 in the Array arr.

for i in 0..9
	arr[i] = i + 1
end

So, 10 locations are created in the array and the numbers, 1 to 10 are stored there.

arr[0] = 1
arr[1] = 2
arr[2] = 3
arr[3] = 4
arr[4] = 5
arr[5] = 6
arr[6] = 7
arr[7] = 8
arr[8] = 9
arr[9] = 10

Similarly, we have used the next for loop to print the values of the array, arr.

for i in 0..9
	puts "The contents of the array are : #{arr[i]}"
end

Next, let us see, how to access the elements of the Array in the next tutorial.

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