Question, how to pull items into an array in a spec?

[adlmtl]

Suppose I have a target:
{ 'a': 1, 'b': 2, 'c': [{ 'd': 3, 'e': 4 }] }

how would I write a spec to produce the output:
{ 'my_output': { 'a_and_b': [1, 2], 'c': [{ 'new_d': 3, 'new_e': 4 }] } }

the part I am hung up on, is how to take 'a' and 'b' and get them into an array...

spec = { 'my_output': { 'a_and_b': ['a', 'b'], 'c': ('c', [{'new_d': 'd', 'new_e': 'e'}]) } }

[kurtbrose]

you want the Fill spec:

>>> from glom import glom, Fill, T
>>> target = {'a': 1, 'b': 2}
>>> glom(target, Fill([T['a'], T['b']]))
[1, 2]

Fill is for "data structure as a template" use cases like this.

in the full context:

>>> target = { 'a': 1, 'b': 2, 'c': [{ 'd': 3, 'e': 4 }] } 
>>> spec = {'my_output': {'a_and_b': Fill([T['a'], T['b']]), 
...                       'c': ('c', [{'new_d': 'd', 'new_e': 'e'}]) } }
>>> glom(target, spec)
{'my_output': {'a_and_b': [1, 2], 'c': [{'new_d': 3, 'new_e': 4}]}}