pick

pick is a DTL operation that keeps only specific keys in a mapping and removes the rest.

Use it when a mapping should be reduced to an allowlist.

YOp

- pick:
    path: user
    keys: [name, email]

Parameters

Parameter	Type	Required	Description
path	string	yes	Path to the mapping to filter.
keys	sequence of strings	yes	Keys to keep. Missing keys are ignored.

Behavior

• Requires the target path to exist.
• Requires the target to be a mapping.
• Removes keys that are not listed.
• Ignores listed keys that do not exist.

Errors

Error	Meaning
PATH_NOT_FOUND	Target path does not exist.
NOT_A_MAPPING	Target is not a mapping.

Example

yops:
  - pick:
      path: config
      keys: [host, port]

Input:

config:
  host: localhost
  port: 5432
  secret: abc

Output:

config:
  host: localhost
  port: 5432