Data Types in YAML¶

In YAML, data types refer to the different kinds of data that can be represented within a YAML document. YAML is a human-readable data serialization format often used for configuration files and data exchange between different programming languages.

While YAML itself is not strongly typed like some programming languages, it provides a way to represent various data types, including strings, numbers, booleans, lists, maps (dictionaries), and more.

Scalar Data Type¶

In YAML, a scalar is a single, atomic value. The value of the scalar can be integer, float, string, or boolean.

Here are a few examples of scalars:

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10.5
hello
hello world
"hello : world"
true
false
2023-12-10

Here's a YAML document using scalars:

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name: Reyansh Kharga
age: 25
weight: 67.8
isPresent: true
enrollmentDate: 2023-12-10

Sequence Data Type¶

In YAML, a sequence is represented by a list of items.

There are two ways to represent a sequence in YAML:

1. Using a hyphen - followed by a space, and each item is placed on a new line with the same indentation level.
2. Using comma-separated items.

Sequence Using Hyphen¶

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fruits:
  - apple
  - banana
  - mango

Sequence Using Comma-Separated Items¶

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fruits: [apple, banana, mango]

Nested Sequence¶

A nested sequence in YAML refers to a situation where you have a sequence that contains another sequence as one of its elements.

In simpler terms, it's a list (or array) of items where one or more of those items is another list.

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fruits:
  - apples
  - bananas
  - oranges
  - berries:
    - strawberries
    - blueberries
  - grapes

Map Data Type¶

In YAML, the map data type is used to represent an unordered collection of key-value pairs. It is similar to a dictionary in other programming languages like Python.

Here are a few examples.

1. Simple Map¶

The following YAML code represents a map with four key-value pairs.

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name: Reyansh
age: 25
weight: 67.8
isPresent: true

2. Complex Map¶

Here's an example of a map with two key-value pairs. The key friends holds a list as its value.

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name: Reyansh Kharga
friends:
  - Adam
  - John
  - Sachin

3. Nested Map¶

In this example, name is a nested map with two key-value pairs.

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name:
  firstName: Reyansh
  lastName: Kharga
age: 25
weight: 67.8

4. More Complex Map¶

In this example we have multiple level of nesting and includes values which are sequences.

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apiVersion: v1
kind: Pod
metadata:
  name: my-pod
  namespace: dev
  labels:
    app: my-app
spec:
  containers:
    - name: nginx
      image: nginx:latest
    - name: busybox
      image: busybox:latest

Note that the item containers is a list of maps.