ALL ABOUT
ARRAYS

NOTEBOOK

presented by Anna Mendoza

L.A. Ruby Montly Meetups

what are
ARRAYS?

Arrays are...

An Array is a sequential collection of items in

which each item can be indexed.

In Ruby, (unlike many other languages) a single Array

can hold items of mixed data types such as strings,

integers and floats or even a method-call

which returns some value:

   
a1 = [1,'two', 3.0, array_length(a0)]

The first item in an array has the index 0,
which means that the final item has an index equal
to the total number of items in the array minus 1.
Given the following array, this is how
to obtain the values of the first and last items:

a1[0] # returns 1st item (at index 0) a1[3] # returns 4th item (at index 3)

Creating Arrays

In common with many other programming languages,

Ruby uses square brackets to delimit an array.

You can easily create an array, fill it with some

comma-delimited values and assign it to a variable:

arr = ['one','two','three','four']

Arrays are...

You can reference an item in an array by placing
its index between square brackets.
If the index is invalid, nil is returned:

   
arr = ['a', 'b', 'c']
puts(arr[0]) # shows a‟ puts(arr[1]) # shows b‟ puts(arr[2]) # shows c‟
puts(arr[3]) # nil

ALL ABOUT
ARRAYS

NOTEBOOK

presented by Anna Mendoza

L.A. Ruby Montly Meetups

what are
ARRAYS?

Arrays are...

`a1 = [1,'two', 3.0, array_length(a0)]`

The first item in an array has the index 0,
which means that the final item has an index equal
to the total number of items in the array minus 1.
Given the following array, this is how
to obtain the values of the first and last items:

`a1[0] # returns 1st item (at index 0) a1[3] # returns 4th item (at index 3)`

Creating Arrays

arr = ['one','two','three','four']

Arrays are...

`arr = ['a', 'b', 'c'] puts(arr[0]) # shows a‟ puts(arr[1]) # shows b‟ puts(arr[2]) # shows c‟ puts(arr[3]) # nil`

And that's what ARRAYS are!

THANK YOU!!

ANNA ( @CURVECOMM )

Present this....

All About Arrays

All About Arrays

Anna Mendoza

ALL ABOUT ARRAYS

NOTEBOOK

presented by Anna Mendoza

L.A. Ruby Montly Meetups

what are ARRAYS?

Arrays are...

a1 = [1,'two', 3.0, array_length(a0)]

The first item in an array has the index 0, which means that the final item has an index equal to the total number of items in the array minus 1. Given the following array, this is how to obtain the values of the first and last items:

a1[0] # returns 1st item (at index 0) a1[3] # returns 4th item (at index 3)

Creating Arrays

arr = ['one','two','three','four']

Arrays are...

arr = ['a', 'b', 'c'] puts(arr[0]) # shows a‟ puts(arr[1]) # shows b‟ puts(arr[2]) # shows c‟ puts(arr[3]) # nil

And that's what ARRAYS are!

THANK YOU!!

ANNA ( @CURVECOMM )

Present this....

All About Arrays

More from Anna Mendoza

ALL ABOUT
ARRAYS

what are
ARRAYS?

`a1 = [1,'two', 3.0, array_length(a0)]`

The first item in an array has the index 0,
which means that the final item has an index equal
to the total number of items in the array minus 1.
Given the following array, this is how
to obtain the values of the first and last items:

`a1[0] # returns 1st item (at index 0) a1[3] # returns 4th item (at index 3)`

`arr = ['a', 'b', 'c'] puts(arr[0]) # shows a‟ puts(arr[1]) # shows b‟ puts(arr[2]) # shows c‟ puts(arr[3]) # nil`