- args(+Key, +Structs, -Args)
- Extract arguments from a list of structures
- group_by_key(+Key, +Structs, -Grouped)
- Partition a list into sublists by key
- group_with_key(+Key, +Structs, -Grouped)
- Partition a list into sublists by key
- inserta(+Key, +Struct, +Old, -New)
- Insert Struct into a sorted list
- insertz(+Key, +Struct, +Old, -New)
- Insert Struct into a sorted list
- lists_structs(?Lists, ?Structs)
- Mapping between a structure of lists and a list of structures
- same_key_prefix(+Key, +All, -KeyVal, -Prefix, -Rest)
- Get the maximum prefix of a list with identical key values
- separate_by_key(+Key, +Value, +All, -Matches, -Others)
- Partition the elements of a list according to a key value
- terms_functor(?Structs, ?Length, ?Name, ?Arity)
- All list elements have the given functor or atomic value
- update(+Key, +Struct, +Old, -New)
- Incorporate Struct into a duplicate-free sorted list
This library contains predicates that operate on lists of structures, in particular structures where one argument can be considered a `key'. Such lists are very common, and often occur in sorted form.
The ECLiPSe kernel and other libraries support such lists as well, e.g.
If you have declared your structures using the :- local(struct(...)) declaration, then you can use field names to identify the key arguments in all these predicates, e.g.
:- local struct(emp(name,age,salary)).
?- Emps = [emp{name:joe,salary:100}, emp{name:bob,salary:200}],
sort(salary of emp, >=, Emps, Descending),
args(name of emp, Descending, Names).
Emps = [emp(joe, _, 100), emp(bob, _, 200)]
Descending = [emp(bob, _, 200), emp(joe, _, 100)]
Names = [bob, joe]
yes