diff --git a/src/Binder/Binder.cpp b/src/Binder/Binder.cpp
index 01dfcf9..504073d 100644
--- a/src/Binder/Binder.cpp
+++ b/src/Binder/Binder.cpp
@@ -599,8 +599,15 @@ namespace Porygon::Binder {
                                                     expression->GetStartPosition(), expression->GetLength());
                 }
                 break;
-            default:
+            case UnaryOperatorKind::Count:
+                if (operandType->IsCountable()){
+                    return new BoundUnaryExpression(operand, BoundUnaryOperation::Count,
+                                                    NumericScriptType::AwareInt,
+                                                    expression->GetStartPosition(), expression->GetLength());
+                }
                 break;
+            default:
+                throw Exception("Unknown unary operator was called.");
         }
         this->_scriptData->Diagnostics->LogError(Diagnostics::DiagnosticCode::NoUnaryOperationFound,
                                                  expression->GetStartPosition(),
diff --git a/src/Binder/BoundOperators.hpp b/src/Binder/BoundOperators.hpp
index 40389bb..ffb1d27 100644
--- a/src/Binder/BoundOperators.hpp
+++ b/src/Binder/BoundOperators.hpp
@@ -23,6 +23,7 @@ namespace Porygon::Binder {
 
     enum class BoundUnaryOperation {
         Negation,
+        Count,
         LogicalNegation,
     };
 }
diff --git a/src/Evaluator/EvalValues/NumericalTableEvalValue.cpp b/src/Evaluator/EvalValues/NumericalTableEvalValue.cpp
index 8e46c27..50c9d46 100644
--- a/src/Evaluator/EvalValues/NumericalTableEvalValue.cpp
+++ b/src/Evaluator/EvalValues/NumericalTableEvalValue.cpp
@@ -1,5 +1,6 @@
 #include "NumericalTableEvalValue.hpp"
 #include "../Iterator/NumericalKeyIterator.hpp"
+#include "../../Utilities/Random.hpp"
 
 inline Porygon::Evaluation::Iterator *Porygon::Evaluation::NumericalTableEvalValue::GetKeyIterator() const {
     return new NumericalKeyIterator(this);
@@ -7,6 +8,14 @@ inline Porygon::Evaluation::Iterator *Porygon::Evaluation::NumericalTableEvalVal
 
 Porygon::Evaluation::NumericalTableEvalValue::NumericalTableEvalValue(shared_ptr<vector<EvalValuePointer>> table) :
         _table(std::move(table)),
-        _hash(rand())
+        _hash(Utilities::Random::Get())
 {
 }
+
+Porygon::Evaluation::EvalValue *
+Porygon::Evaluation::NumericalTableEvalValue::UnaryOperation(Porygon::Binder::BoundUnaryOperation operation) const {
+    if (operation == Porygon::Binder::BoundUnaryOperation::Count){
+        return new NumericEvalValue(static_cast<int64_t>(this->_table->size()));
+    }
+    return EvalValue::UnaryOperation(operation);
+}
diff --git a/src/Evaluator/EvalValues/NumericalTableEvalValue.hpp b/src/Evaluator/EvalValues/NumericalTableEvalValue.hpp
index 9a5c1db..ff2112b 100644
--- a/src/Evaluator/EvalValues/NumericalTableEvalValue.hpp
+++ b/src/Evaluator/EvalValues/NumericalTableEvalValue.hpp
@@ -69,7 +69,9 @@ namespace Porygon::Evaluation {
         [[nodiscard]]
         inline shared_ptr<vector<EvalValuePointer>> GetTable() const{
             return _table;
-        };
+        }
+
+        EvalValue *UnaryOperation(Binder::BoundUnaryOperation operation) const override;;
     };
 }
 
diff --git a/src/Evaluator/EvalValues/StringEvalValue.hpp b/src/Evaluator/EvalValues/StringEvalValue.hpp
index 5c3ef85..816524b 100644
--- a/src/Evaluator/EvalValues/StringEvalValue.hpp
+++ b/src/Evaluator/EvalValues/StringEvalValue.hpp
@@ -4,6 +4,7 @@
 
 #include <string>
 #include "EvalValue.hpp"
+#include "NumericEvalValue.hpp"
 #include "../../Utilities/HashedString.hpp"
 
 using namespace std;
@@ -68,6 +69,13 @@ namespace Porygon::Evaluation {
             auto str = stringStream.str();
             return new StringEvalValue(str);
         }
+
+        [[nodiscard]] EvalValue *UnaryOperation(Binder::BoundUnaryOperation operation) const override {
+            if (operation == Binder::BoundUnaryOperation ::Count){
+                return new NumericEvalValue(static_cast<int64_t >(_value->size()));
+            }
+            return EvalValue::UnaryOperation(operation);
+        }
     };
 }
 
diff --git a/src/Evaluator/EvalValues/TableEvalValue.cpp b/src/Evaluator/EvalValues/TableEvalValue.cpp
index 26f2495..2995a5b 100644
--- a/src/Evaluator/EvalValues/TableEvalValue.cpp
+++ b/src/Evaluator/EvalValues/TableEvalValue.cpp
@@ -1,6 +1,15 @@
 #include "TableEvalValue.hpp"
 #include "../Iterator/SimpleKeyIterator.hpp"
+#include "NumericEvalValue.hpp"
 
 inline Porygon::Evaluation::Iterator * Porygon::Evaluation::TableEvalValue::GetKeyIterator() const {
     return new TableKeyIterator(this);
 }
+
+Porygon::Evaluation::EvalValue *
+Porygon::Evaluation::TableEvalValue::UnaryOperation(Porygon::Binder::BoundUnaryOperation operation) const {
+    if (operation == Porygon::Binder::BoundUnaryOperation::Count){
+        return new NumericEvalValue(static_cast<int64_t>(this->_table->size()));
+    }
+    return EvalValue::UnaryOperation(operation);
+}
diff --git a/src/Evaluator/EvalValues/TableEvalValue.hpp b/src/Evaluator/EvalValues/TableEvalValue.hpp
index a663099..843653f 100644
--- a/src/Evaluator/EvalValues/TableEvalValue.hpp
+++ b/src/Evaluator/EvalValues/TableEvalValue.hpp
@@ -83,7 +83,9 @@ namespace Porygon::Evaluation {
         [[nodiscard]]
         inline _Rb_tree_const_iterator<pair<const Utilities::HashedString, EvalValuePointer>> GetTableIteratorEnd() const{
             return _table->cend();
-        };
+        }
+
+        EvalValue *UnaryOperation(Binder::BoundUnaryOperation operation) const override;;
     };
 }
 
diff --git a/src/Parser/Lexer.cpp b/src/Parser/Lexer.cpp
index 6b4badc..cb1022c 100644
--- a/src/Parser/Lexer.cpp
+++ b/src/Parser/Lexer.cpp
@@ -103,6 +103,8 @@ namespace Porygon::Parser {
                 }
                 this->ScriptData->Diagnostics->LogError(Diagnostics::DiagnosticCode::UnexpectedCharacter, this->_position - 1, 1);
                 return new SimpleToken(TokenKind::BadToken, this->_position - 1, 1);
+            case '#':
+                return new SimpleToken(TokenKind::HashToken, this->_position - 1, 1);
             case '0':
             case '1':
             case '2':
diff --git a/src/Parser/Parser.cpp b/src/Parser/Parser.cpp
index 5127286..cfcd631 100644
--- a/src/Parser/Parser.cpp
+++ b/src/Parser/Parser.cpp
@@ -362,6 +362,7 @@ namespace Porygon::Parser {
         switch (kind) {
             case TokenKind::PlusToken:
             case TokenKind::MinusToken:
+            case TokenKind::HashToken:
             case TokenKind::NotKeyword:
                 return OperatorPrecedence::Unary;
             default:
@@ -375,6 +376,8 @@ namespace Porygon::Parser {
                 return UnaryOperatorKind::Identity;
             case TokenKind::MinusToken:
                 return UnaryOperatorKind::Negation;
+            case TokenKind::HashToken :
+                return UnaryOperatorKind::Count;
             case TokenKind::NotKeyword:
                 return UnaryOperatorKind::LogicalNegation;
             default: // This should never trigger, so throw.
diff --git a/src/Parser/TokenKind.hpp b/src/Parser/TokenKind.hpp
index b90503d..3ab41b9 100644
--- a/src/Parser/TokenKind.hpp
+++ b/src/Parser/TokenKind.hpp
@@ -19,6 +19,7 @@ namespace Porygon::Parser {
         LessEquals,
         Greater,
         GreaterEquals,
+        HashToken,
 
         OpenParenthesis,
         CloseParenthesis,
diff --git a/src/Parser/UnaryOperatorKind.hpp b/src/Parser/UnaryOperatorKind.hpp
index 305a42e..0a6818e 100644
--- a/src/Parser/UnaryOperatorKind.hpp
+++ b/src/Parser/UnaryOperatorKind.hpp
@@ -6,6 +6,7 @@ namespace Porygon::Parser {
     enum class UnaryOperatorKind {
         Identity,
         Negation,
+        Count,
         LogicalNegation,
     };
 }
diff --git a/src/ScriptTypes/ScriptType.cpp b/src/ScriptTypes/ScriptType.cpp
index 786eedd..f2f731e 100644
--- a/src/ScriptTypes/ScriptType.cpp
+++ b/src/ScriptTypes/ScriptType.cpp
@@ -1,5 +1,7 @@
 #include "../Script.hpp"
 #include "../UserData/UserDataFunctionType.hpp"
+#include "ScriptType.hpp"
+
 
 namespace Porygon{
     inline bool ScriptType::CanBeIndexedWith(const ScriptType *) const{
@@ -76,6 +78,14 @@ namespace Porygon{
         return ToString(this->_class);
     }
 
+    bool ScriptType::IsCountable() const {
+        return false;
+    }
+
+    bool StringScriptType::IsCountable() const {
+        return true;
+    }
+
     extern "C"{
         ScriptType* CreateScriptType(Porygon::TypeClass t){
             return new ScriptType(t);
diff --git a/src/ScriptTypes/ScriptType.hpp b/src/ScriptTypes/ScriptType.hpp
index 3d86141..059f311 100644
--- a/src/ScriptTypes/ScriptType.hpp
+++ b/src/ScriptTypes/ScriptType.hpp
@@ -51,6 +51,8 @@ namespace Porygon{
 
         [[nodiscard]] virtual CastResult CastableTo(const shared_ptr<const ScriptType>& castType, bool explicitCast) const;
 
+        [[nodiscard]] virtual bool IsCountable() const;
+
         static std::string ToString(TypeClass c);
         [[nodiscard]] virtual std::string ToString() const;
     };
@@ -145,6 +147,8 @@ namespace Porygon{
         inline uint32_t GetHashValue() const{
             return _hashValue;
         }
+
+        bool IsCountable() const override;
     };
 
     class NumericalTableScriptType : public ScriptType{
diff --git a/src/ScriptTypes/TableScriptType.hpp b/src/ScriptTypes/TableScriptType.hpp
index 5c823ed..dccdd64 100644
--- a/src/ScriptTypes/TableScriptType.hpp
+++ b/src/ScriptTypes/TableScriptType.hpp
@@ -65,6 +65,10 @@ namespace Porygon{
         shared_ptr<const ScriptType> GetIteratorKeyType() const final {
             return make_shared<ScriptType>(TypeClass::Any);
         }
+
+        bool IsCountable() const override {
+            return true;
+        }
     };
 }
 
diff --git a/src/UserData/UserDataCollections/UserDataCollectionType.hpp b/src/UserData/UserDataCollections/UserDataCollectionType.hpp
index 396740a..3d791f7 100644
--- a/src/UserData/UserDataCollections/UserDataCollectionType.hpp
+++ b/src/UserData/UserDataCollections/UserDataCollectionType.hpp
@@ -20,7 +20,8 @@ namespace Porygon::UserData {
                   _iterable(iterable)
         {}
 
-        static shared_ptr<UserDataCollectionType> CreateIndexable(const shared_ptr<const ScriptType>& keyType, const shared_ptr<const ScriptType>& valueType){
+        static shared_ptr<UserDataCollectionType> CreateIndexable(const shared_ptr<const ScriptType>& keyType,
+                const shared_ptr<const ScriptType>& valueType){
             return make_shared<UserDataCollectionType>(keyType, valueType, true, true);
         }
 
@@ -65,6 +66,10 @@ namespace Porygon::UserData {
                 return _valueType;
             }
         }
+
+        [[nodiscard]] bool IsCountable() const override {
+            return true;
+        }
     };
 }
 
diff --git a/src/UserData/UserDataCollections/UserDataCollectionValue.cpp b/src/UserData/UserDataCollections/UserDataCollectionValue.cpp
index 894b47f..7873d9e 100644
--- a/src/UserData/UserDataCollections/UserDataCollectionValue.cpp
+++ b/src/UserData/UserDataCollections/UserDataCollectionValue.cpp
@@ -8,8 +8,9 @@ UserDataCollectionType* CreateCollectionType(const ScriptType* keyType, const Sc
 UserDataCollectionValue* CreateCollectionValue(UserDataCollectionType* type, void* obj,
                                                const EvalValue* (*get)(void*, const EvalValue*),
                                                void (*set)(void*, const EvalValue*, const EvalValue*),
-                                               Iterator* (*getIterator)(void*)){
-    return new UserDataCollectionValue(shared_ptr<UserDataCollectionType>(type), new UserDataCollectionHelper(obj, get, set, getIterator));
+                                               Iterator* (*getIterator)(void*), size_t (getSize)(void*)){
+    return new UserDataCollectionValue(shared_ptr<UserDataCollectionType>(type),
+            new UserDataCollectionHelper(obj, get, set, getIterator, getSize));
 }
 }
 }
diff --git a/src/UserData/UserDataCollections/UserDataCollectionValue.hpp b/src/UserData/UserDataCollections/UserDataCollectionValue.hpp
index 5ec7625..c027f40 100644
--- a/src/UserData/UserDataCollections/UserDataCollectionValue.hpp
+++ b/src/UserData/UserDataCollections/UserDataCollectionValue.hpp
@@ -6,6 +6,7 @@
 #include "UserDataCollectionType.hpp"
 #include "../../Evaluator/EvalValues/EvalValue.hpp"
 #include "../../Utilities/Random.hpp"
+#include "../../Evaluator/EvalValues/NumericEvalValue.hpp"
 
 using namespace Porygon::Evaluation;
 
@@ -15,12 +16,14 @@ namespace Porygon::UserData {
         const EvalValue* (*_get)(void*, const EvalValue*);
         void (*_set)(void*, const EvalValue* , const EvalValue*);
         Iterator* (*_getIterator)(void*);
+        size_t (*_getLength)(void*);
     public:
         UserDataCollectionHelper(void* parentObject,
                                  const EvalValue* (*get)(void*, const EvalValue*),
                                  void (*set)(void*, const EvalValue*, const EvalValue*),
-                                 Iterator* (*getIterator)(void*))
-                                 : _parentObject(parentObject), _get(get), _set(set), _getIterator(getIterator){}
+                                 Iterator* (*getIterator)(void*), size_t (*getLength)(void*))
+                                 : _parentObject(parentObject), _get(get), _set(set), _getIterator(getIterator),
+                                   _getLength(getLength){}
 
         const EvalValue* Get(const EvalValue* key) const{
             return _get(_parentObject, key);
@@ -33,6 +36,10 @@ namespace Porygon::UserData {
         [[nodiscard]] Iterator* GetIterator() const{
             return _getIterator(_parentObject);
         }
+
+        [[nodiscard]] size_t GetLength() const{
+            return _getLength(_parentObject);
+        }
     };
 
     class UserDataCollectionValue : public Evaluation::EvalValue{
@@ -46,7 +53,7 @@ namespace Porygon::UserData {
         }
     public:
 
-        UserDataCollectionValue(shared_ptr<const ScriptType> type, const UserDataCollectionHelper* helper)
+        UserDataCollectionValue(const shared_ptr<const ScriptType>& type, const UserDataCollectionHelper* helper)
                 : _type(dynamic_pointer_cast<const UserDataCollectionType>(type)), _helper(helper), _hash(Utilities::Random::Get())
         {
         }
@@ -85,6 +92,13 @@ namespace Porygon::UserData {
             _helper->Set(key, value);
             delete value;
         }
+
+        [[nodiscard]] EvalValue *UnaryOperation(Binder::BoundUnaryOperation operation) const override {
+            if (operation == Binder::BoundUnaryOperation::Count){
+                return new NumericEvalValue(static_cast<int64_t>(_helper->GetLength()));
+            }
+            return EvalValue::UnaryOperation(operation);
+        }
     };
 }
 
diff --git a/src/UserData/UserDataTemplates.hpp b/src/UserData/UserDataTemplates.hpp
index b1f9892..285e3ca 100644
--- a/src/UserData/UserDataTemplates.hpp
+++ b/src/UserData/UserDataTemplates.hpp
@@ -96,6 +96,8 @@ Porygon::Utilities::HashedString* Convert(const char* k){
                     auto val = ((T_USERDATA*)obj)->fieldName; \
                     auto size = val.size(); \
                     return new Porygon::UserData::UserDataCollectionRangeIterator(0, size); \
+                }, [](void* obj) -> size_t{ \
+                    return ((T_USERDATA*)obj)->fieldName.size(); \
                 } \
             ) \
         ) \