Map Library
The Map Library is split into two classes. UNihiloMapLibrary is a
templated C++ library covering the full operation set. UNihiloMapLibrary_BP
exposes a typed Blueprint subset for common key/value type combinations: String→String,
String→Int, String→Float,
String→Object, Int→String,
Int→Int, Int→Float,
Int→Object, Object→String, and
Object→Object.
info
All functions are stateless and return new maps — none mutate the input. In C++, pass any key/value types via
the templated versions. In Blueprint, use the typed suffix variants (e.g. Merge_StringInt).
| Function |
Description |
|---|
|
| ContainsValue |
Returns true if any entry in the map has the given
Value. Blueprint typed variants available.
|
| GetKeys |
Returns all keys as a TArray<K>. Blueprint typed variants available.
|
| GetValues |
Returns all values as a TArray<V>. Blueprint typed variants available.
|
| FindKeysForValue |
Returns all keys whose mapped value equals Value. Useful for reverse lookups
without inverting the full map. Blueprint typed variants available.
|
| Function |
Description |
|---|
|
| Invert |
Returns a new map with keys and values swapped — a TMap<V, K>.
Duplicate values in the original will overwrite earlier entries. Blueprint typed variants available.
|
| Filter |
Returns a new map containing only entries where the predicate returns true.
The predicate receives both the key and value. C++ only.
|
| TransformValues |
Keeps all keys, applying a transformer function to produce new values of a different type.
Returns a TMap<K, NewV>. C++ only.
|
| TransformKeys |
Keeps all values, applying a transformer function to produce new keys of a different type.
Returns a TMap<NewK, V>. C++ only.
|
| Function |
Description |
|---|
|
| Merge |
Combines two maps into one. On key conflicts, the second map's value wins. Blueprint typed variants available.
|
| MergeWith |
Combines two maps using a custom conflict resolver. When both maps contain the same key, the resolver
receives both values and returns the one to keep. C++ only.
|
| Function |
Description |
|---|
|
| ToArray |
Converts the map to a TArray<TPair<K, V>>. In Blueprint,
typed variants output parallel OutKeys and OutValues arrays instead.
|
| FromArrays |
Builds a map from parallel Keys and Values arrays.
Length is clamped to the shorter array. Blueprint typed variants available.
|
| IndexBy |
Builds a map from an array by extracting each element's key via a selector function.
bOverwriteDuplicates controls whether later entries replace earlier ones on key collisions. C++ only.
|
| Function |
Description |
|---|
|
| CountWhere |
Returns the number of entries where the predicate returns true.
The predicate receives both key and value. C++ only.
|
| AnyMatch / AllMatch |
Predicate-based boolean checks across all entries. Both predicates receive the key and value. C++ only.
|