How can I do string concatenation, or string replacement in YAML?

Question

I have this:

user_dir: /home/user
user_pics: /home/user/pics

How could I use the user_dir for user_pics? If I have to specify

Answer 1

If you are using python with PyYaml, joining strings is possible within the YAML file. Unfortunately this is only a python solution, not a universal one:

with os.path.join:

user_dir: &home /home/user
user_pics: !!python/object/apply:os.path.join [*home, pics]

with string.join (for completeness sake - this method has the flexibility to be used for multiple forms of string joining:

user_dir: &home /home/user
user_pics: !!python/object/apply:string.join [[*home, pics], /]