Advanced Data Types.md

Sequences (Lists)

!!seq here means sequence.

student: !!seq
 - marks
 - name
 - rol_no

We can also do something like

cities: [new delhi, mumbai, amritsar, gurdaspur]

We can also keep some of the keys of the Seqeuence empty. This is known as Sparse Sequence .

- hey
- how
- 
- hello
- 

Nested Sequence

- 
 - cool 
 - awesome
 - sexy
- 
 - bad
 - ugly
 - rugged

The - with no value, specifies start of a new object.

Maps i.e key: value pairs

we can use !!map data type

We can also define Nested Mappings. Map within a map.

name: Shubh Karman 
role:
 age: 22
 job: student

We can also do something like

name: Shubh Karman 
role: {age: 22, job: student}

Pairs

In pairs, keys may have duplicate values. !!pairs to declare this data type.

pairExample: !!pairs
  - job: student
  - job: teacher
  
# This can also be seen as an array of hash tables
pairExamples: !!pairs [job: student, job: teacher]

Sets

Set in YAML can be seen as an data structure containing unique keys only.

names: !!set
 ? Shubh Karman
 ? Apoorv
 ? Rahul

Dictionary

Dictionary is used when you want to represent entire sequence as a value. This is represented by !!omap

people: !!omap
 - Kunal:
	 name: Shubh Karman
	 age: 22 
 - Rahul: 
	 name: Rahul Sharma 
	 age: 23

Anchors

When their some repeated properties over multiple declarations you can declare them in a single data structure and use them in your other declarations.

So, basically which property / declaration you want to copy and where do you want to copy it.

likings: &likes
	fav: mango
	notFav: grapes

person1: 
 name: Shubh
 <<: *likes	

<<: *anchorName will copy paste all the properties represented by anchorName. To declare it use &.