key/2

SWI-Prolog Did You Know Did you know? test

Search Documentation:

Predicate key/2

HOME
DOWNLOAD
DOCUMENTATION
- Manual
- Packages
- FAQ
- Command line
- PlDoc
- Bluffers▶
- License
- Publications
- Rev 7 Extensions
TUTORIALS
- Beginner▶
- Advanced▶
- Web applications▶
- Semantic web▶
  - ClioPatria
  - RDF namespaces
- Graphics▶
  - XPCE
  - GUI options
- Machine learning▶
  - Probabilistic Logic Programming
- External collections▶
  - Meta level tutorials
- For packagers▶
  - Linux packages
COMMUNITY
COMMERCIAL
WIKI
- Login
- View changes
- Sandbox
- Wiki help
- All tags

Availability::- use_module(library(janus)).(can be autoloaded)

Source

[nondet]key(+Dict, ?Key)

True when Key is a key in Dict. Backtracking enumerates all known keys.

Compatibility: PIP. Note that this predicate handle a SWI-Prolog dict, a {k:v, ...} term as well as py({k:v, ...}.