YAML Do I need quotes for strings in YAML

Question

I am trying to write a YAML dictionary for internationalisation of a Rails project  I am a little confused though  as in some files I see strings in double-quotes and in some without  A few points to consider   example 1 - all strings use double quotes  example 2 - no strings  except the last two  use quotes  the YAML cookbook says  Enclosing strings in double quotes allows you to use escaping to represent ASCII and Unicode characters  Does this mean I need to use double quotes only when I want to escape some characters  If yes - why do they use double quotes everywhere in the first example - only for the sake of unity   stylistic reasons  the last two lines of example 2 use   - the non-specific tag  while the last two lines of the first example don t - and they both work   My question is  what are the rules for using the different types of quotes in YAML  Could it be said that   in general  you don t need quotes  if you want to escape characters use double quotes  use   with single quotes  when

User · Accepted Answer

After a brief review of the YAML cookbook cited in the question and some testing, here's my interpretation:

In general, you don't need quotes.
Use quotes to force a string, e.g. if your key or value is 10 but you want it to return a String and not a Fixnum, write '10' or "10".
Use quotes if your value includes special characters, (e.g. :, {, }, [, ], ,, &, *, #, ?, |, -, <, >, =, !, %, @, \).
Single quotes let you put almost any character in your string, and won't try to parse escape codes. '\n' would be returned as the string \n.
Double quotes parse escape codes. "\n" would be returned as a line feed character.
The exclamation mark introduces a method, e.g. !ruby/sym to return a Ruby symbol.

Seems to me that the best approach would be to not use quotes unless you have to, and then to use single quotes unless you specifically want to process escape codes.

Update

"Yes" and "No" should be enclosed in quotes (single or double) or else they will be interpreted as TrueClass and FalseClass values:

en:
  yesno:
    'yes': 'Yes'
    'no': 'No'

User · Answer

I had this concern when working on a Rails application with Docker  My most preferred approach is to generally not use quotes  This includes not using quotes for   variables like   RAILS ENV  values separated by a colon     like postgres-log  var log postgresql other strings values  I  however  use double-quotes for integer values that need to be converted to strings like   docker-compose version like version   quot 3 8 quot  port numbers like  quot 8080 8080 quot   However  for special cases like booleans  floats  integers  and other cases  where using double-quotes for the entry values could be interpreted as strings  please do not use double-quotes  Here s a sample docker-compose yml file to explain this concept  version   quot 3 quot   services    traefik      image  traefik v2 2 1     command        - --api insecure true   Don t do that in production       - --providers docker true       - --providers docker exposedbydefault false       - --entrypoints web address  80     ports        -  quot 80 80 quot        -  quot 8080 8080 quot      volumes        -  var run docker sock  var run docker sock ro  That s all  I hope this helps

[syntax] YAML: Do I need quotes for strings in YAML?

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