What are monoids and how to use them - Scala tutorial

This video will introduce you to the Monoid and Semigroup type classes, their powers and rules that they have to obey. You'll see examples of common instances of these type classes as well as some more interesting ones, like the Map monoid. You'll also find out why a single type could have more than one lawful instance of the Monoid type class.

Table of contents:
0:00 - Introduction
0:50 - Definitions of Semigroup and Monoid
5:14 - Example: adding Integers
6:30 - Example: concatenating Strings
7:04 - Example: List monoid
8:31 - Alternative monoids: Product monoid for Int
10:28 - combineAll
11:38 - foldMap
13:35 - More advanced example: Map monoid (accumulating lists of values)
16:28 - Map monoid: grouping list elements by size
17:34 - Map monoid: counting occurences of elements in list
17:58 - Recap: what we learned
18:28 - Sneak peek of the Monoids and Semigroups libraries

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[heartlyu]

Thank you so much for the video . this is first time, someone has really explained monoids this clearly. Also i would like to see and entire application built in scala, this would be just for reference.

[rsalama]

Very nice video, thanks! What editor are you using?

[halyph]

what vscode extension do you use for this “presentation”?

[kovacshuni]

Nice how you do live coding, make more videos.

[mrGrey]

no one javascript guy sets a dislike ;)