Return type | Name and parameters |
---|---|
boolean
|
any(Closure closure)
Iterates over the entries of a map, and checks whether a predicate is valid for at least one entry. |
boolean
|
asBoolean()
Coerce a map instance to a boolean value. |
Map
|
asImmutable()
A convenience method for creating an immutable map. |
Map
|
asSynchronized()
A convenience method for creating a synchronized Map. |
Object
|
asType(Class clazz)
Coerces this map to the given type, using the map's keys as the public method names, and values as the implementation. |
List
|
collect(Closure transform)
Iterates through this Map transforming each map entry into a new value using the transform closure
returning a list of transformed values.
|
Collection
|
collect(Collection collector, Closure transform)
Iterates through this Map transforming each map entry into a new value using the transform closure
returning the collector with all transformed values added to it.
|
Map
|
collectEntries(Closure transform)
Iterates through this Map transforming each entry using the transform closure
and returning a map of the transformed entries.
|
Map
|
collectEntries(Map collector, Closure transform)
Iterates through this Map transforming each map entry using the transform closure
returning a map of the transformed entries.
|
Collection
|
collectMany(Closure projection)
Projects each item from a source map to a result collection and concatenates (flattens) the resulting collections adding them into a collection. |
Collection
|
collectMany(Collection collector, Closure projection)
Projects each item from a source map to a result collection and concatenates (flattens) the resulting collections adding them into the collector .
|
Number
|
count(Closure closure)
Counts the number of occurrences which satisfy the given closure from inside this map. |
Map
|
countBy(Closure closure)
Groups the members of a map into groups determined by the supplied mapping closure and counts the frequency of the created groups. |
Map
|
drop(int num)
Drops the given number of key/value pairs from the head of this map if they are available. |
Map
|
dropWhile(Closure condition)
Create a suffix of the given Map by dropping as many entries as possible from the front of the original Map such that calling the given closure condition evaluates to true when passed each of the dropped entries (or key/value pairs). |
Map
|
each(Closure closure)
Allows a Map to be iterated through using a closure. |
Map
|
eachWithIndex(Closure closure)
Allows a Map to be iterated through using a closure. |
boolean
|
equals(Map other)
Compares two Maps treating coerced numerical values as identical. |
boolean
|
every(Closure closure)
Iterates over the entries of a map, and checks whether a predicate is valid for all entries. |
Entry
|
find(Closure closure)
Finds the first entry matching the closure condition. |
Map
|
findAll(Closure closure)
Finds all entries matching the closure condition. |
Object
|
findResult(Closure closure)
Returns the first non-null closure result found by passing each map entry to the closure, otherwise null is returned. |
Object
|
findResult(Object defaultResult, Closure closure)
Returns the first non-null closure result found by passing each map entry to the closure, otherwise the defaultResult is returned. |
Collection
|
findResults(Closure filteringTransform)
Iterates through the map transforming items using the supplied closure and collecting any non-null results. |
Object
|
get(Object key, Object defaultValue)
Looks up an item in a Map for the given key and returns the value - unless there is no entry for the given key in which case add the default value to the map and return that. |
Object
|
getAt(Object key)
Support the subscript operator for a Map. |
Map
|
groupBy(Closure closure)
Groups the members of a map into sub maps determined by the supplied mapping closure. |
Map
|
groupBy(Object closures)
Groups the members of a map into sub maps determined by the supplied mapping closures. |
Map
|
groupBy(List closures)
Groups the members of a map into sub maps determined by the supplied mapping closures. |
Map
|
groupEntriesBy(Closure closure)
Groups all map entries into groups determined by the supplied mapping closure. |
Object
|
inject(Object initialValue, Closure closure)
Iterates through the given Map, passing in the initial value to the 2-arg Closure along with the first item (or 3-arg Closure along with the first key and value). |
Map
|
intersect(Map right)
Create a Map composed of the intersection of both maps. |
boolean
|
isCase(Object switchValue)
'Case' implementation for maps which tests the groovy truth value obtained using the 'switch' operand as key. |
Map
|
leftShift(Map other)
Overloads the left shift operator to provide an easy way to put one maps entries into another map. |
Map
|
leftShift(Entry entry)
Overloads the left shift operator to provide an easy way to append Map.Entry values to a Map. |
Entry
|
max(Closure closure)
Selects an entry in the map having the maximum calculated value as determined by the supplied closure. |
Entry
|
min(Closure closure)
Selects an entry in the map having the minimum calculated value as determined by the supplied closure. |
Map
|
minus(Map removeMe)
Create a Map composed of the entries of the first map minus the entries of the given map. |
Map
|
plus(Collection entries)
Returns a new Map containing all entries from self and entries ,
giving precedence to entries .
|
Map
|
plus(Map right)
Returns a new Map containing all entries from left and right ,
giving precedence to right .
|
Map
|
putAll(Collection entries)
Provides an easy way to append multiple Map.Entry values to a Map. |
Object
|
putAt(Object key, Object value)
A helper method to allow maps to work with subscript operators |
Map
|
reverseEach(Closure closure)
Allows a Map to be iterated through in reverse order using a closure. |
Map
|
sort()
Sorts the elements from the given map into a new ordered Map using the natural ordering of the keys to determine the ordering. |
Map
|
sort(Closure closure)
Sorts the elements from the given map into a new ordered map using the closure as a comparator to determine the ordering. |
Map
|
sort(Comparator comparator)
Sorts the elements from the given map into a new ordered Map using the specified key comparator to determine the ordering. |
SpreadMap
|
spread()
Synonym for Map#toSpreadMap(). |
Map
|
subMap(K[] keys)
Creates a sub-Map containing the given keys. |
Map
|
subMap(Collection keys)
Creates a sub-Map containing the given keys. |
Map
|
take(int num)
Returns a new map containing the first num elements from the head of this map.
|
Map
|
takeWhile(Closure condition)
Returns the longest prefix of this Map where each entry (or key/value pair) when passed to the given closure evaluates to true. |
String
|
toMapString()
Returns the string representation of this map. |
String
|
toMapString(int maxSize)
Returns the string representation of this map. |
SpreadMap
|
toSpreadMap()
Returns a new SpreadMap from this map.
|
Map
|
withDefault(Closure init)
Wraps a map using the decorator pattern with a wrapper that intercepts all calls to get(key) .
|
Iterates over the entries of a map, and checks whether a predicate is valid for at least one entry. If the closure takes one parameter then it will be passed the Map.Entry otherwise if the closure takes two parameters then it will be passed the key and the value.
assert [2:3, 4:5, 5:10].any { key, value -> key * 2 == value } assert ![2:3, 4:5, 5:10].any { entry -> entry.key == entry.value * 2 }
closure
- the 1 or 2 arg closure predicate used for matchingCoerce a map instance to a boolean value. A map is coerced to false if it's empty, and to true otherwise.
assert [:] as Boolean == false assert [a:2] as Boolean == true
A convenience method for creating an immutable map.
A convenience method for creating a synchronized Map.
Coerces this map to the given type, using the map's keys as the public method names, and values as the implementation. Typically the value would be a closure which behaves like the method implementation.
clazz
- the target typeIterates through this Map transforming each map entry into a new value using the transform
closure
returning a list of transformed values.
assert [a:1, b:2].collect { key, value -> key*value } == ["a", "bb"] assert [3:20, 2:30].collect { entry -> entry.key * entry.value } == [60, 60]
transform
- the transformation closure which can take one (Map.Entry) or two (key, value) parametersIterates through this Map transforming each map entry into a new value using the transform
closure
returning the collector
with all transformed values added to it.
assert [a:1, b:2].collect( [] as HashSet ) { key, value -> key*value } == ["a", "bb"] as Set assert [3:20, 2:30].collect( [] as HashSet ) { entry -> entry.key * entry.value } == [60] as Set
collector
- the Collection to which transformed values are addedtransform
- the transformation closure which can take one (Map.Entry) or two (key, value) parametersIterates through this Map transforming each entry using the transform
closure
and returning a map of the transformed entries.
assert [a:1, b:2].collectEntries { key, value -> [value, key] } == [1:'a', 2:'b'] assert [a:1, b:2].collectEntries { key, value -> [(value*10): key.toUpperCase()] } == [10:'A', 20:'B']Note: When using the list-style of result, the behavior is '
def (key, value) = listResultFromClosure
'.
While we strongly discourage using a list of size other than 2, Groovy's normal semantics apply in this case;
throwing away elements after the second one and using null for the key or value for the case of a shortened list.
If your Map doesn't support null keys or values, you might get a runtime error, e.g. NullPointerException or IllegalArgumentException.
transform
- the closure used for transforming, which can take one (Map.Entry) or two (key, value) parameters and
should return a Map.Entry, a Map or a two-element list containing the resulting key and valueIterates through this Map transforming each map entry using the transform
closure
returning a map of the transformed entries.
assert [a:1, b:2].collectEntries( [:] ) { k, v -> [v, k] } == [1:'a', 2:'b'] assert [a:1, b:2].collectEntries( [30:'C'] ) { key, value -> [(value*10): key.toUpperCase()] } == [10:'A', 20:'B', 30:'C']Note: When using the list-style of result, the behavior is '
def (key, value) = listResultFromClosure
'.
While we strongly discourage using a list of size other than 2, Groovy's normal semantics apply in this case;
throwing away elements after the second one and using null for the key or value for the case of a shortened list.
If your collector Map doesn't support null keys or values, you might get a runtime error, e.g. NullPointerException or IllegalArgumentException.
collector
- the Map into which the transformed entries are puttransform
- the closure used for transforming, which can take one (Map.Entry) or two (key, value) parameters and
should return a Map.Entry, a Map or a two-element list containing the resulting key and valueProjects each item from a source map to a result collection and concatenates (flattens) the resulting collections adding them into a collection.
def map = [bread:3, milk:5, butter:2] def result = map.collectMany{ k, v -> k.startsWith('b') ? k.toList() : [] } assert result == ['b', 'r', 'e', 'a', 'd', 'b', 'u', 't', 't', 'e', 'r']
projection
- a projecting Closure returning a collection of itemsProjects each item from a source map to a result collection and concatenates (flattens) the resulting
collections adding them into the collector
.
def map = [bread:3, milk:5, butter:2] def result = map.collectMany(['x']){ k, v -> k.startsWith('b') ? k.toList() : [] } assert result == ['x', 'b', 'r', 'e', 'a', 'd', 'b', 'u', 't', 't', 'e', 'r']
collector
- an initial collection to add the projected items toprojection
- a projecting Closure returning a collection of itemsCounts the number of occurrences which satisfy the given closure from inside this map. If the closure takes one parameter then it will be passed the Map.Entry. Otherwise, the closure should take two parameters and will be passed the key and value.
Example usage:
assert [a:1, b:1, c:2, d:2].count{ k,v -> k == 'a' || v == 2 } == 3
closure
- a 1 or 2 arg Closure condition applying on the entriesGroups the members of a map into groups determined by the supplied mapping closure and counts the frequency of the created groups. The closure will be passed a Map.Entry or key and value (depending on the number of parameters the closure accepts) and should return the key that each item should be grouped under. The resulting map will have an entry for each 'group' key returned by the closure, with values being the frequency counts for that 'group'.
def result = [a:1,b:2,c:3,d:4,e:5].countBy { it.value % 2 } assert result == [0:2, 1:3]
closure
- a closure mapping entries to frequency count keysDrops the given number of key/value pairs from the head of this map if they are available.
def strings = [ 'a':10, 'b':20, 'c':30 ] assert strings.drop( 0 ) == [ 'a':10, 'b':20, 'c':30 ] assert strings.drop( 2 ) == [ 'c':30 ] assert strings.drop( 5 ) == [:]If the map instance does not have ordered keys, then this function could drop a random
num
entries. Groovy by default uses LinkedHashMap, so this shouldn't be an issue in the main.
num
- the number of elements to drop from this mapnum
ones, or else the empty map, if this map has
less than num
elements.Create a suffix of the given Map by dropping as many entries as possible from the front of the original Map such that calling the given closure condition evaluates to true when passed each of the dropped entries (or key/value pairs).
def shopping = [milk:1, bread:2, chocolate:3] assert shopping.dropWhile{ it.key.size() < 6 } == [chocolate:3] assert shopping.dropWhile{ it.value % 2 } == [bread:2, chocolate:3] assert shopping.dropWhile{ k, v -> k.size() + v <= 7 } == [chocolate:3]If the map instance does not have ordered keys, then this function could appear to drop random entries. Groovy by default uses LinkedHashMap, so this shouldn't be an issue in the main.
condition
- a 1 (or 2) arg Closure that must evaluate to true for the
entry (or key and value) to continue dropping elementsAllows a Map to be iterated through using a closure. If the closure takes one parameter then it will be passed the Map.Entry otherwise if the closure takes two parameters then it will be passed the key and the value.
def result = "" [a:1, b:3].each { key, value -> result += "$key$value" } assert result == "a1b3"
def result = "" [a:1, b:3].each { entry -> result += entry } assert result == "a=1b=3"In general, the order in which the map contents are processed cannot be guaranteed. In practise, specialized forms of Map, e.g. a TreeMap will have its contents processed according to the natural ordering of the map.
closure
- the 1 or 2 arg closure applied on each entry of the mapAllows a Map to be iterated through using a closure. If the closure takes two parameters then it will be passed the Map.Entry and the item's index (a counter starting at zero) otherwise if the closure takes three parameters then it will be passed the key, the value, and the index.
def result = "" [a:1, b:3].eachWithIndex { key, value, index -> result += "$index($key$value)" } assert result == "0(a1)1(b3)"
def result = "" [a:1, b:3].eachWithIndex { entry, index -> result += "$index($entry)" } assert result == "0(a=1)1(b=3)"
closure
- a 2 or 3 arg Closure to operate on each itemCompares two Maps treating coerced numerical values as identical.
Example usage:
assert [a:2, b:3] == [a:2L, b:3.0]
other
- the Map being compared toIterates over the entries of a map, and checks whether a predicate is valid for all entries. If the closure takes one parameter then it will be passed the Map.Entry otherwise if the closure takes two parameters then it will be passed the key and the value.
def map = [a:1, b:2.0, c:2L] assert !map.every { key, value -> value instanceof Integer } assert map.every { entry -> entry.value instanceof Number }
closure
- the 1 or 2 arg Closure predicate used for matchingFinds the first entry matching the closure condition. If the closure takes two parameters, the entry key and value are passed. If the closure takes one parameter, the Map.Entry object is passed.
assert [a:1, b:3].find { it.value == 3 }.key == "b"
closure
- a 1 or 2 arg Closure conditionFinds all entries matching the closure condition. If the closure takes one parameter then it will be passed the Map.Entry. Otherwise if the closure should take two parameters, which will be the key and the value.
If the self
map is one of TreeMap, LinkedHashMap, Hashtable
or Properties, the returned Map will preserve that type, otherwise a HashMap will
be returned.
Example usage:
def result = [a:1, b:2, c:4, d:5].findAll { it.value % 2 == 0 } assert result.every { it instanceof Map.Entry } assert result*.key == ["b", "c"] assert result*.value == [2, 4]
closure
- a 1 or 2 arg Closure condition applying on the entriesReturns the first non-null closure result found by passing each map entry to the closure, otherwise null is returned. If the closure takes two parameters, the entry key and value are passed. If the closure takes one parameter, the Map.Entry object is passed.
assert "Found b:3" == [a:1, b:3].findResult { if (it.value == 3) return "Found ${it.key}:${it.value}" } assert null == [a:1, b:3].findResult { if (it.value == 9) return "Found ${it.key}:${it.value}" } assert "Found a:1" == [a:1, b:3].findResult { k, v -> if (k.size() + v == 2) return "Found $k:$v" }
closure
- a 1 or 2 arg Closure that returns a non-null value when processing should stop and a value should be returnedReturns the first non-null closure result found by passing each map entry to the closure, otherwise the defaultResult is returned. If the closure takes two parameters, the entry key and value are passed. If the closure takes one parameter, the Map.Entry object is passed.
assert "Found b:3" == [a:1, b:3].findResult("default") { if (it.value == 3) return "Found ${it.key}:${it.value}" } assert "default" == [a:1, b:3].findResult("default") { if (it.value == 9) return "Found ${it.key}:${it.value}" } assert "Found a:1" == [a:1, b:3].findResult("default") { k, v -> if (k.size() + v == 2) return "Found $k:$v" }
defaultResult
- an Object that should be returned if all closure results are nullclosure
- a 1 or 2 arg Closure that returns a non-null value when processing should stop and a value should be returnedIterates through the map transforming items using the supplied closure and collecting any non-null results. If the closure takes two parameters, the entry key and value are passed. If the closure takes one parameter, the Map.Entry object is passed.
Example:
def map = [a:1, b:2, hi:2, cat:3, dog:2] def result = map.findResults { k, v -> k.size() == v ? "Found $k:$v" : null } assert result == ["Found a:1", "Found hi:2", "Found cat:3"]
filteringTransform
- a 1 or 2 arg Closure that should return either a non-null transformed value or null for items which should be discardedLooks up an item in a Map for the given key and returns the value - unless there is no entry for the given key in which case add the default value to the map and return that.
def map=[:] map.get("a", []) << 5 assert map == [a:[5]]
key
- the key to lookup the value ofdefaultValue
- the value to return and add to the map for this key if
there is no entry for the given keySupport the subscript operator for a Map.
def map = [a:10] assert map["a"] == 10
key
- an Object as a key for the mapGroups the members of a map into sub maps determined by the supplied mapping closure. The closure will be passed a Map.Entry or key and value (depending on the number of parameters the closure accepts) and should return the key that each item should be grouped under. The resulting map will have an entry for each 'group' key returned by the closure, with values being the map members from the original map that belong to each group. (If instead of a map, you want a list of map entries use {code}groupEntriesBy{code}.)
If the self
map is one of TreeMap, Hashtable or Properties,
the returned Map will preserve that type, otherwise a LinkedHashMap will
be returned.
def result = [a:1,b:2,c:3,d:4,e:5,f:6].groupBy { it.value % 2 } assert result == [0:[b:2, d:4, f:6], 1:[a:1, c:3, e:5]]
closure
- a closure mapping entries on keysGroups the members of a map into sub maps determined by the supplied
mapping closures. Each closure will be passed a Map.Entry or key and
value (depending on the number of parameters the closure accepts) and
should return the key that each item should be grouped under. The
resulting map will have an entry for each 'group path' returned by all
closures, with values being the map members from the original map that
belong to each such 'group path'.
If the self
map is one of TreeMap, Hashtable, or Properties,
the returned Map will preserve that type, otherwise a LinkedHashMap will
be returned.
def result = [a:1,b:2,c:3,d:4,e:5,f:6].groupBy({ it.value % 2 }, { it.key.next() }) assert result == [1:[b:[a:1], d:[c:3], f:[e:5]], 0:[c:[b:2], e:[d:4], g:[f:6]]]If an empty array of closures is supplied the IDENTITY Closure will be used.
closures
- an array of closures that map entries on keysGroups the members of a map into sub maps determined by the supplied
mapping closures. Each closure will be passed a Map.Entry or key and
value (depending on the number of parameters the closure accepts) and
should return the key that each item should be grouped under. The
resulting map will have an entry for each 'group path' returned by all
closures, with values being the map members from the original map that
belong to each such 'group path'.
If the self
map is one of TreeMap, Hashtable, or Properties,
the returned Map will preserve that type, otherwise a LinkedHashMap will
be returned.
def result = [a:1,b:2,c:3,d:4,e:5,f:6].groupBy([{ it.value % 2 }, { it.key.next() }]) assert result == [1:[b:[a:1], d:[c:3], f:[e:5]], 0:[c:[b:2], e:[d:4], g:[f:6]]]If an empty list of closures is supplied the IDENTITY Closure will be used.
closures
- a list of closures that map entries on keysGroups all map entries into groups determined by the supplied mapping closure. The closure will be passed a Map.Entry or key and value (depending on the number of parameters the closure accepts) and should return the key that each item should be grouped under. The resulting map will have an entry for each 'group' key returned by the closure, with values being the list of map entries that belong to each group. (If instead of a list of map entries, you want an actual map use {code}groupBy{code}.)
def result = [a:1,b:2,c:3,d:4,e:5,f:6].groupEntriesBy { it.value % 2 } assert result[0]*.key == ["b", "d", "f"] assert result[1]*.value == [1, 3, 5]
closure
- a 1 or 2 arg Closure mapping entries on keysIterates through the given Map, passing in the initial value to the 2-arg Closure along with the first item (or 3-arg Closure along with the first key and value). The result is passed back (injected) into the closure along with the second item. The new result is injected back into the closure along with the third item and so on until the entire collection has been used. Also known as foldLeft or reduce in functional parlance. Examples:
def map = [a:1, b:2, c:3] assert map.inject([]) { list, k, v -> list + [k] * v } == ['a', 'b', 'b', 'c', 'c', 'c']
initialValue
- some initial valueclosure
- a 2 or 3 arg ClosureCreate a Map composed of the intersection of both maps. Any entries that exist in both maps are added to the resultant map.
assert [4:4,5:5] == [1:1,2:2,3:3,4:4,5:5].intersect([4:4,5:5,6:6,7:7,8:8])
assert [1: 1, 2: 2, 3: 3, 4: 4].intersect( [1: 1.0, 2: 2, 5: 5] ) == [1:1, 2:2]
right
- a map'Case' implementation for maps which tests the groovy truth value obtained using the 'switch' operand as key. For example:
switch( 'foo' ) { case [foo:true, bar:false]: assert true break default: assert false }
switchValue
- the switch valueOverloads the left shift operator to provide an easy way to put
one maps entries into another map. This allows the compact syntax
map1 << map2
; otherwise it's just a synonym for
putAll
though it returns the original map rather than
being a void
method. Example usage:
def map = [a:1, b:2] map << [c:3, d:4] assert map == [a:1, b:2, c:3, d:4]
other
- another Map whose entries should be added to the original Map.Overloads the left shift operator to provide an easy way to append Map.Entry values to a Map.
entry
- a Map.Entry to be added to the Map.Selects an entry in the map having the maximum calculated value as determined by the supplied closure. If more than one entry has the maximum value, an arbitrary choice is made between the entries having the maximum value.
If the closure has two parameters it is used like a traditional Comparator. I.e. it should compare its two parameters for order, returning a negative integer, zero, or a positive integer when the first parameter is less than, equal to, or greater than the second respectively. Otherwise, the Closure is assumed to take a single parameter and return a Comparable (typically an Integer) which is then used for further comparison. An example:
def zoo = [monkeys:6, lions:5, tigers:7] def mostCommonEntry = zoo.max{ it.value } assert mostCommonEntry.value == 7 def leastCommonEntry = zoo.max{ a, b -> b.value <=> a.value } // double negative! assert leastCommonEntry.value == 5Edge case for multiple max values:
def zoo = [monkeys:6, lions:5, tigers:7] def lengthOfNamePlusNumber = { e -> e.key.size() + e.value } def ans = zoo.max(lengthOfNamePlusNumber) // one of [monkeys:6, tigers:7] assert lengthOfNamePlusNumber(ans) == 13
closure
- a 1 or 2 arg Closure used to determine the correct orderingSelects an entry in the map having the minimum calculated value as determined by the supplied closure. If more than one entry has the minimum value, an arbitrary choice is made between the entries having the minimum value.
If the closure has two parameters it is used like a traditional Comparator. I.e. it should compare its two parameters for order, returning a negative integer, zero, or a positive integer when the first parameter is less than, equal to, or greater than the second respectively. Otherwise, the Closure is assumed to take a single parameter and return a Comparable (typically an Integer) which is then used for further comparison.
def zoo = [monkeys:6, lions:5, tigers:7] def leastCommonEntry = zoo.min{ it.value } assert leastCommonEntry.value == 5 def mostCommonEntry = zoo.min{ a, b -> b.value <=> a.value } // double negative! assert mostCommonEntry.value == 7Edge case for multiple min values:
def zoo = [monkeys:6, lions:5, tigers:7] def lastCharOfName = { e -> e.key[-1] } def ans = zoo.min(lastCharOfName) // some random entry assert lastCharOfName(ans) == 's'
closure
- a 1 or 2 arg Closure used to determine the correct orderingCreate a Map composed of the entries of the first map minus the entries of the given map.
removeMe
- the entries to remove from the mapReturns a new Map
containing all entries from self
and entries
,
giving precedence to entries
. Any keys appearing in both Maps
will appear in the resultant map with values from the entries
operand. If self
map is one of TreeMap, LinkedHashMap, Hashtable
or Properties, the returned Map will preserve that type, otherwise a HashMap will
be returned.
entries
- a Collection of Map.Entry items to be added to the Map.Returns a new Map
containing all entries from left
and right
,
giving precedence to right
. Any keys appearing in both Maps
will appear in the resultant map with values from the right
operand. If the left
map is one of TreeMap, LinkedHashMap, Hashtable
or Properties, the returned Map will preserve that type, otherwise a HashMap will
be returned.
Roughly equivalent to Map m = new HashMap(); m.putAll(left); m.putAll(right); return m;
but with some additional logic to preserve the left
Map type for common cases as
described above.
assert [a:10, b:20] + [a:5, c:7] == [a:5, b:20, c:7]
right
- a MapProvides an easy way to append multiple Map.Entry values to a Map.
entries
- a Collection of Map.Entry items to be added to the Map.A helper method to allow maps to work with subscript operators
key
- an Object as a key for the mapvalue
- the value to put into the mapAllows a Map to be iterated through in reverse order using a closure. In general, the order in which the map contents are processed cannot be guaranteed. In practise, specialized forms of Map, e.g. a TreeMap will have its contents processed according to the reverse of the natural ordering of the map.
closure
- the 1 or 2 arg closure applied on each entry of the mapSorts the elements from the given map into a new ordered Map using the natural ordering of the keys to determine the ordering. The original map is unchanged.
map = [ba:3, cz:6, ab:5].sort() assert map*.value == [5, 3, 6]
Sorts the elements from the given map into a new ordered map using the closure as a comparator to determine the ordering. The original map is unchanged.
def map = [a:5, b:3, c:6, d:4].sort { a, b -> a.value <=> b.value } assert map == [b:3, d:4, a:5, c:6]
closure
- a Closure used as a comparatorSorts the elements from the given map into a new ordered Map using the specified key comparator to determine the ordering. The original map is unchanged.
def map = [ba:3, cz:6, ab:5].sort({ a, b -> a[-1] <=> b[-1] } as Comparator) assert map*.value == [3, 5, 6]
comparator
- a ComparatorSynonym for Map#toSpreadMap().
Creates a sub-Map containing the given keys. This method is similar to List.subList() but uses keys rather than index ranges. The original map is unaltered.
def orig = [1:10, 2:20, 3:30, 4:40] assert orig.subMap([1, 3] as int[]) == [1:10, 3:30] assert orig.subMap([2, 4] as Integer[]) == [2:20, 4:40] assert orig.size() == 4
keys
- an array of keysCreates a sub-Map containing the given keys. This method is similar to List.subList() but uses keys rather than index ranges.
assert [1:10, 2:20, 4:40].subMap( [2, 4] ) == [2:20, 4:40]
keys
- a Collection of keysReturns a new map containing the first num
elements from the head of this map.
If the map instance does not have ordered keys, then this function could return a random num
entries. Groovy by default uses LinkedHashMap, so this shouldn't be an issue in the main.
def strings = [ 'a':10, 'b':20, 'c':30 ] assert strings.take( 0 ) == [:] assert strings.take( 2 ) == [ 'a':10, 'b':20 ] assert strings.take( 5 ) == [ 'a':10, 'b':20, 'c':30 ]
num
- the number of elements to take from this mapnum
elements of this map,
or else the whole map if it has less then num
elements.Returns the longest prefix of this Map where each entry (or key/value pair) when passed to the given closure evaluates to true.
def shopping = [milk:1, bread:2, chocolate:3] assert shopping.takeWhile{ it.key.size() < 6 } == [milk:1, bread:2] assert shopping.takeWhile{ it.value % 2 } == [milk:1] assert shopping.takeWhile{ k, v -> k.size() + v <= 7 } == [milk:1, bread:2]If the map instance does not have ordered keys, then this function could appear to take random entries. Groovy by default uses LinkedHashMap, so this shouldn't be an issue in the main.
condition
- a 1 (or 2) arg Closure that must evaluate to true for the
entry (or key and value) to continue taking elementsReturns the string representation of this map. The string displays the
contents of the map, i.e. [one:1, two:2, three:3]
.
Returns the string representation of this map. The string displays the
contents of the map, i.e. [one:1, two:2, three:3]
.
maxSize
- stop after approximately this many characters and append '...'Returns a new SpreadMap
from this map.
The example below shows the various possible use cases:
def fn(Map m) { return m.a + m.b + m.c + m.d } assert fn(a:1, b:2, c:3, d:4) == 10 assert fn(a:1, *:[b:2, c:3], d:4) == 10 assert fn([a:1, b:2, c:3, d:4].toSpreadMap()) == 10 assert fn((['a', 1, 'b', 2, 'c', 3, 'd', 4] as Object[]).toSpreadMap()) == 10 assert fn(['a', 1, 'b', 2, 'c', 3, 'd', 4].toSpreadMap()) == 10 assert fn(['abcd'.toList(), 1..4].transpose().flatten().toSpreadMap()) == 10Note that toSpreadMap() is not normally used explicitly but under the covers by Groovy.
Wraps a map using the decorator pattern with a wrapper that intercepts all calls
to get(key)
. If an unknown key is found, a default value will be
stored into the Map before being returned. The default value stored will be the
result of calling the supplied Closure with the key as the parameter to the Closure.
Example usage:
def map = [a:1, b:2].withDefault{ k -> k.toCharacter().isLowerCase() ? 10 : -10 } def expected = [a:1, b:2, c:10, D:-10] assert expected.every{ e -> e.value == map[e.key] } def constMap = [:].withDefault{ 42 } assert constMap.foo == 42 assert constMap.size() == 1
init
- a Closure which is passed the unknown key