YAML Key-Value Pairs

YAML documents primarily consist of key-value pairs, where keys and values are separated by a colon (:). It is essential to have a space after the colon to differentiate the key from the value.

Supported Data Types

• Integer: Numbers without a decimal.
• Floating Point Numbers: Numbers with a decimal.
• Strings: Text data. Important: Quote strings that contain special characters such as colons (:), braces ({}), pipes (|), or brackets ([]).
• Boolean: Values that are either true or false.
• Dates: Should follow the ISO 8601 format.
• Null Values: Represented as null or ~.

YAML Lists

YAML lists are denoted by a dash (-) and are indented.

• Block Sequence: Each entry starts with a dash and a space (-).
• Flow Sequence: Written as a comma-separated list within square brackets ([]).

Example

fruits:
  - Apple
  - Orange
  - Banana

numbers: [1, 2, 3, 4]

YAML Dictionary

YAML dictionaries group key-value pairs together under a single item.

Example

person:
  name: John Doe
  age: 30
  is_student: false

YAML Lists Containing Dictionaries

YAML allows lists to contain dictionaries, combining both structures.

Example

employees:
  - name: Alice
    position: Developer
  - name: Bob
    position: Designer

YAML Lists Containing Dictionaries Containing Lists

You can nest lists within dictionaries inside a list, creating complex structures.

Example

departments:
  - name: Engineering
    employees:
      - Alice
      - Bob
  - name: Marketing
    employees:
      - Charlie
      - Dana

YAML Pipe (|)

The pipe notation, also known as a literal block, preserves all new lines, indentation, and extra spaces as is.

Example

description: |
  This is a multiline string.
  All new lines and spaces are preserved.

YAML Greater Than Sign (>)

The greater than sign notation, also known as a folded block, renders the text as a single line. New lines are replaced with a single space, while blank lines are converted to new line characters.

Example

description: >
  This is a folded
  multiline string.
  New lines are replaced with spaces.

YAML Comments

Comments in YAML begin with the # sign. They are useful for adding notes or explanations within the document.

Example

# This is a comment
name: John Doe  # This is an inline comment
age: 30

This guide outlines the structure and syntax of YAML, including key-value pairs, lists, dictionaries, and various notation styles for multiline text. Understanding these elements will help you effectively create and manage YAML documents.