YAML:

It was first called Yet Another MarkUp Langugae but now it is Yaml Ain't MarkUp Language.

Definition:

Applications written with different technologies or languages which have different Data Structures can transfer data to each other using a Common/ Standerd Format. YAML, JSON and XML are these formats

It is a Data Serialization Language

• Data Serialization: Translation of Object (Code + Data) into stream of bytes that saves the state of this object in a form that is transmittable. Using Serialization, data can be converted into code and code can be converted into data again.

Benifits of YAML:

• Simple and easy to read
• Nice and Strict Syntax
• Most Languages use it
• More powerful when representing complex data

Note: Any JSON input can be converted to YAML output and vice virse

SYNTAX

Data Type

Yaml Automatically Determines the data type if not specified

name: Hammad
age: 20
graduate: no

But you can specify a dataType

Syntax --> variable: !!datatype value
age: !!int 20

Some Common are

zero: !!int 0
positiveNum: !!int 45
negativeNum: !!int -27
commaValue: !!int 245_000 #245,000

Other Types

PI: !!float 3.14
infinite: !!infinite .inf
not a num: !!nan .nan
booleanValue: !!boolean no
nameString: !!str Hammad
nullDataType: !!null null #null or NULL or ~

Lists

- Item1
- Item2
- Item3

Nested Lists

-
 - Item1
 - Item2
 - Item3

-
 - Item1
 - Item2
 - Item3

Block Type / Object

ObjectTypeKeyValue:
  KeyValue: Pair
  KeyValue2: Pair2

Or

ObjectTypeSimpleList: -Item1
  -Item2
  -Item3

You want to display multiple line in your browser but you want your browser to treat it as a single line #Use ">"

aboutInSingleLine: >-
  I am a CS student
  Currently Learning DevOps
  and Android Dev

Same as

about2: I am a CS student Currently Learning DevOps and Android Dev

Remember Indentation (one space) is very important here

aboutTwoMultipleLine: |-
  I am a CS student
  Currently Learning DevOps
  and Android Dev

Single Key but have two Values

pairExample: 
  - job: Student
  - job: Teacher

Set

SetExample:
?Hammad: Student
?Danish: Graduate
?Zubair: Freelancer

Dictionary

People:
 -Hammad:
  - Role: Student
  - Age: 20
 -Kunal:
  -Role: Teacher
  -Age: 78 

Reusing Properties

Likes: &likes
 - Fruites: Mango
 - Food: Biryani

Person1:
 -Name: Hammad
 <<: *likes