YAML

Introduction

YAML is a data serialisation language designed to be directly writable and readable by humans

Scalar types 

n1: 1            # integer          
n2: 1.234        # float      

s1: 'abc'        # string        
s2: "abc"        # string           
s3: abc          # string           

b: false         # boolean type 

d: 2015-04-05    # date type

Equavalent JSON 

{ "n1": 1, "n2": 1.234, "s1": "abc", "s2": "abc", "s3": "abc", "b": false, "d": "2015-04-05" }

Use spaces to indent. There must be space between the element parts.

Variables 

some_thing: &VAR_NAME foobar
other_thing: *VAR_NAME

Equavalent JSON 

{ "some_thing": "foobar", "other_thing": "foobar" }

Sequence 

object:
  attributes:
    - a1
    - a2
    - a3
  methods: [getter, setter]

Equavalent JSON 

{ "object": { "attributes": ["a1", "a2", "a3"], "methods": ["getter", "setter"] } }

Sequence of sequences 

my_sequences:
  - [1, 2, 3]
  - [4, 5, 6]

Equavalent JSON 

{ "my_sequences": [ [1, 2, 3], [4, 5, 6] ] }

Comments 

# A single line comment example

# block level comment example
# comment line 1
# comment line 2
# comment line 3

Multiline strings 

description: |
  hello
  world

Equavalent JSON 

{"description": "hello\nworld\n"}

Folded text 

description: >
  hello
  world

Equavalent JSON 

{"description": "hello world\n"}

Hashes 

jack:
  id: 1
  name: Franc
  salary: 5000
  hobby:
    - a
    - b
  loc: {country: "A", city: "A-A"}

Equavalent JSON 

{ "jack": { "id": 1, "name": "Franc", "salary": 5000, "hobby": ["a", "b"], "loc": { "country": "A", "city": "A-A" } } }

Nested dictionaries 

Employee:
  id: 1
  name: "Franc"
  department:
    name: "Sales"
    depid: "11"

Equavalent JSON 

{ "Employee": { "id": 1, "name": "Franc", "department": { "name": "Sales", "depid": "11" } } }

Sequence of dictionaries 

children:
  - name: Jimmy Smith
    age: 15
  - name: Jenny Smith
    age: 12

Equavalent JSON 

{ "children": [ {"name": "Jimmy Smith", "age": 15}, {"name": "Jenny Smith", "age": 12} ] }

Set 

set1: !!set
  ? one
  ? two
set2: !!set {'one', "two"}

Equavalent JSON 

{ "set1": {"one": null, "two": null}, "set2": {"one": null, "two": null} }

Inheritance 

parent: &defaults
  a: 2
  b: 3

child:
  <<: *defaults
  b: 4

Equavalent JSON 

{ "parent": {"a": 2, "b": 3}, "child": {"a": 2, "b": 4} }

Reference 

values: &ref
  - These values
  - will be reused below

other_values:
  i_am_ref: *ref

Equavalent JSON 

{ "values": [ "These values", "will be reused below" ], "other_values": { "i_am_ref": [ "These values", "will be reused below" ] } }

Documents 

---
document: this is doc 1
---
document: this is doc 2
...