Prahlad Inala
Prahlad Inala

Follow

Prahlad Inala

Follow
Introduction to YAML

Introduction to YAML

Prahlad Inala's photo
Prahlad Inala
·Feb 1, 2023·

4 min read

Play this article

Table of contents

What is YAML?

YAML (Yet Another Markup Language) is a human-readable data serialization format used for storing and exchanging data. It is often used for configuration files, data exchange between different programming languages, and in applications where data is stored in a structured format.

Why YAML?

One of the main advantages of YAML is its simplicity and readability. Unlike other data serialization formats, such as XML and JSON, YAML uses indentation to indicate the structure of data, making it easy for humans to read and understand. It is also lightweight, making it an efficient choice for applications that need to store and exchange data.

YAML supports a wide range of data types, including scalar values (strings, numbers, and booleans), lists, and dictionaries (also known as maps or associative arrays). YAML also supports data structures such as arrays, hashes, and complex nested structures, making it a flexible choice for storing complex data.

Another important feature of YAML is its ability to handle null and undefined values, which are represented by the special value “null” in YAML. This makes it easy to represent missing or null values in a consistent manner across different programming languages.

History of YAML

YAML (short for "YAML Ain't Markup Language") was first introduced in 2001 by Clark Evans, Ingy döt Net, and Oren Ben-Kiki. The idea behind YAML was to create a human-friendly and easily readable data serialization format, as an alternative to more complex formats such as XML or JSON.

YAML was inspired by several existing data serialization formats, including JSON and XML, as well as older formats such as S-expressions and configure files. The creators of YAML aimed to create a format that was easy to read and write, with a minimum of syntax and complexity.

Since its introduction, YAML has become increasingly popular as a data serialization format, particularly in the field of software development. It is used for a wide range of purposes, including configuration files, data storage, and data exchange between different systems.

YAML has also been adopted as a standard for data serialization by many organizations and projects, including the OpenStack project and the Ansible configuration management tool. It has become one of the most popular data serialization formats in use today, due to its simplicity, flexibility, and human-friendly syntax.

Where YAML is used?

YAML is often used in web development, where it is used to configure web applications, and in DevOps, where it is used to store configuration data for software deployments. It is also widely used in the Ansible automation framework, where it is used to store configuration data for managing IT infrastructure.

In summary, YAML is a simple, lightweight, and human-readable data serialization format that is widely used for storing and exchanging data in a wide range of applications. Its simplicity and readability, combined with its support for complex data structures, make it a popular choice for many applications.

Few Examples of YAML Code

Example 1: Storing a Scalar Value

# Single line scalar value
name: John Doe

Example 2: Storing a List

# List of items
fruits:
  - Apple
  - Orange
  - Banana

Example 3: Storing a Dictionary

# Dictionary/Map
person:
  name: John Doe
  age: 30
  address:
    street: 123 Main St.
    city: San Francisco
    state: CA

Example 4: Storing Complex Data Structures

# Complex data structure
employees:
  - name: John Doe
    age: 30
    role: Manager
  - name: Jane Doe
    age: 25
    role: Developer
  - name: Bob Smith
    age: 35
    role: Designer

Example 5: Storing Multi-line Strings

# Multi-line string
description: |
  This is a long description
  that spans multiple lines.

Example 6: Storing Dates and Times

# Date and time
date: 2022-12-25
time: 12:00:00

Example 7: Storing Boolean Values

# Boolean values
is_active: true
is_deleted: false

Example 8: Storing Null Values

# Null value
value: null

Example 9: Storing Anchors and Aliases

# Anchors and aliases
address: &address
  street: 123 Main St.
  city: San Francisco
  state: CA

person:
  name: John Doe
  age: 30
  address: *address

Example 10: Storing Nested Data Structures

# Nested data structures
employees:
  - name: John Doe
    age: 30
    skills:
      - Python
      - JavaScript
      - Ruby
  - name: Jane Doe
    age: 25
    skills:
      - Java
      - Go
      - Scala

Example 11: Storing Complex Mappings

# Complex mapping
person:
  name: John Doe
  age: 30
  details:
    address:
      street: 123 Main St.
      city: San Francisco
      state: CA
    phone_numbers:
      - 123-456-7890
      - 987-654-3210

Example 12: Using References in YAML

# References
employee_template: &employee_template
  name:
  age:
  role:

employees:
  - <<: *employee_template
    name: John Doe
    age: 30
    role: Manager
  - <<: *employee_template
    name: Jane Doe
    age: 25
    role: Developer

Example 13: Storing Metadata in YAML

# Metadata
---
title: Employee List
created_at: 2022-12-25 12:00:00
version: 1.0

employees:
  - name: John Doe
    age: 30
    role: Manager
  - name: Jane Doe
    age: 25
    role: Developer
...

Did you find this article valuable?

Support Prahlad Inala by becoming a sponsor. Any amount is appreciated!

See recent sponsors Learn more about Hashnode Sponsors
 
Share this