Understanding YAML Block Scalars - Folded and Literal Styles

Note#103

notes
Published

2023-07-03

YAML block scalars are specific types of data in YAML that span multiple lines. There are two styles: “folded” and “literal”.

Folded Style (>)

The “folded style” in YAML is denoted using the greater-than sign (>). It is used for text data where:

  • Newlines should be replaced with spaces, effectively creating a single long line from the source text.
  • If you want to insert a newline in the parsed text, you need to use a double newline in the source.

Here’s an example:

folded_style: >
  This is a very long
  sentence that spans several
  lines in the YAML but will be
  rendered as a single line
  in the resulting string.

In the above YAML, the value of folded_style will be: This is a very long sentence that spans several lines in the YAML but will be rendered as a single line in the resulting string.

Literal Style (|)

The “literal style” in YAML is denoted using the pipe character (|). It is used for text data where:

  • Newlines should be preserved exactly as they are given in the source text.

Here’s an example:

literal_style: |
  This is a sentence.
  This is another sentence.
  This is yet another sentence.

In the above YAML, the value of literal_style will be:

This is a sentence.
This is another sentence.
This is yet another sentence.

For both the folded and literal styles, the initial level of indentation (before the > or |) is removed in the parsed text, but any additional indentation is preserved.