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final class

sys::Map

sys::Obj
  sys::Map

Map is a hash map of key/value pairs.

See docCookbook::Maps for coding examples.

Slots

add

M add(K key, V val)

Add the specified key/value pair to the map. If the key is already mapped, then throw the ArgErr. Return this. If key does not return true for Obj.isImmutable, then throw NotImmutableErr. If key is null throw NullErr. Throw ReadonlyErr if readonly.

addAll

M addAll(M m)

Append the specified map to this map by adding every key/value in m in this map. If any key in m is already mapped then this method will fail (any previous keys will remain mapped potentially leaving this map in an inconsistent state). Return this. Throw ReadonlyErr if readonly. This method is semanatically equivalent to:

m.each |K k, V v| { this.add(k, v) }
caseInsensitive

Bool caseInsensitive

This field configures case sensitivity for maps with Str keys. When set to true, Str keys are compared without regard to case for the following methods: get, containsKey, set, add, setAll, addAll, and remove methods. Only ASCII character case is taken into account. The original case is preserved (keys aren't made all lower or upper case). This field defaults to false.

Getting this field is idempotent. If you attempt to set this method on a map which is not empty or not typed to use Str keys, then throw UnsupportedOperation. Throw ReadonlyErr if set when readonly.

clear

Void clear()

Remove all key/value pairs from the map. Return this. Throw ReadonlyErr if readonly.

containsKey

Bool containsKey(K key)

Return if the specified key is mapped. This method is idempotent.

dup

M dup()

Create a shallow duplicate copy of this Map. The keys and values themselves are not duplicated. This method is idempotent.

each

Void each(|V, K| c)

Call the specified function for every key/value in the list. This method is idempotent.

equals

override Bool equals(Obj that)

Two Maps are equal if they have the same number of equal key/value pairs.

exclude

M exclude(|V, K -> Bool| c)

Return a new map containing the key/value pairs for which c returns false. If c returns true for every item, then return an empty list. The inverse of this method is findAll(). This method is idempotent.

Example:

map := ["off":0, "slow":50, "fast":100]
map.exclude |Int v->Bool| { return v == 0 } => ["slow":50, "fast":100]
find

V find(|V, K -> Bool| c)

Return the first value in the map for which c returns true. If c returns false for every pair, then return null. This method is idempotent.

findAll

M findAll(|V, K -> Bool| c)

Return a new map containing the key/value pairs for which c returns true. If c returns false for every item, then return an empty map. The inverse of this method is exclude(). This method is idempotent.

get

V get(K key, V def := null)

Get the value for the specified key. If key is not mapped, then return the value of def (null by default). This method is idempotent. Shortcut is a[key].

hash

override Int hash()

Return platform dependent hashcode based on hash of the keys and values.

isEmpty

Bool isEmpty()

Return if size() == 0. This method is idempotent.

isRO

Bool isRO()

Return if this Map is readonly. A readonly Map is guaranteed to be immutable (although its values may be mutable themselves). Any attempt to modify a readonly Map will result in ReadonlyErr. Use rw() to get a read-write Map from a readonly Map. Methods documented as idempotent may be used safely with a readonly Map. This method is idempotent.

isRW

Bool isRW()

Return if this Map is read-write. A read-write Map is mutable and may be modified. Use ro() to get a readonly Map from a read-write Map. This method is idempotent.

keys

K[] keys()

Get a list of all the mapped keys. This method is idempotent.

make

new make(Type type)

Constructor with of type (must be Map type).

map

M map(Map acc, |V, K -> Obj| c)

Create a new map with the same keys, but apply the specified closure to generate new values. This method is idempotent.

Example:

m := [2:2, 3:3, 4:4]
x := m.map(Str:Int[:]) |Int v->Obj| { return v*2 }
x => [2:4, 3:6, 4:8]
reduce

Obj reduce(Obj init, |Obj, V, K -> Obj| c)

Reduce is used to iterate through every value in the map to reduce the map into a single value called the reduction. The initial value of the reduction is passed in as the init parameter, then passed back to the closure along with each item. This method is idempotent.

Example:

m := ["2":2, "3":3, "4":4]
m.reduce(100) |Obj r, Int v->Obj| { return (Int)r + v } => 109
remove

V remove(K key)

Remove the key/value pair identified by the specified key from the map and return the value. If the key was not mapped then return null. Throw ReadonlyErr if readonly.

ro

M ro()

Get a readonly, immutable Map instance with the same contents as this Map (although its values may be mutable themselves). If this Map is already readonly, then return this. Only methods documented as idempotent may be used safely with a readonly Map, all others will throw ReadonlyErr. This method is idempotent.

rw

M rw()

Get a read-write, mutable Map instance with the same contents as this Map. If this Map is already read-write, then return this. This method is idempotent.

set

M set(K key, V val)

Set the value for the specified key. If the key is already mapped, this overwrites the old value. If key is not yet mapped this adds the key/value pair to the map. Return this. If key does not return true for Obj.isImmutable, then throw NotImmutableErr. If key is null throw NullErr. Throw ReadonlyErr if readonly.

setAll

M setAll(M m)

Append the specified map to this map by setting every key/value in m in this map. Keys in m not yet mapped are added and keys already mapped are overwritten. Return this. Throw ReadonlyErr if readonly. This method is semanatically equivalent to:

m.each |K k, V v| { this.set(k, v) }
size

Int size()

Get the number of key/value pairs in the list. This method is idempotent.

toImmutable

M toImmutable()

Return an immutable Map which returns true for Obj.isImmtable. If this Map is already immutable, then return this. This method is effectively a "deep ro()" which guarantees that if any values are Lists or Maps, then they are made immutable by recursively calling toImmutable. All other values must return true for Obj.isImmutable, otherwise NotImmutableErr is thrown. This method must be used whenever setting a const Map field. This method is idempotent.

toStr

override Str toStr()

Return a string representation the Map. This method is idempotent.

values

V[] values()

Get a list of all the mapped values. This method is idempotent.