Question

I’m writing a YAML file which contains some configuration data. It will be read in to Python as a dictionary of dictionaries. Some of the data needs to be repeated under a different key. Is there a way to do this without large amounts of cut and paste?

Here is an example of the yaml file:

BLOCK1:
  a: 1
  b: 2
  c: 3

BLOCK2:
  a: 4
  b: 5
  c: 6

BLOCK3: # Basically the same as BLOCK2
  a: 4  # Is there a way to make this a link to BLOCK2 or a copy of BLOCK2?
  b: 5
  c: 6

Answer 1

Yes, there is. Take a look at: http://pyyaml.org/wiki/PyYAMLDocumentation#Aliases

Basically, you should do:

BLOCK1: 
  a: 1
  b: 2
  c: 3

BLOCK2: &block
  a: 4
  b: 5
  c: 6

BLOCK3: *block

And the results will be:

{'BLOCK1': {'a': 1, 'b': 2, 'c': 3},
 'BLOCK2': {'a': 4, 'b': 5, 'c': 6},
 'BLOCK3': {'a': 4, 'b': 5, 'c': 6}}