LINQ in Update

LINQ (Language Integrated Query) is powerful and expressive, but it is generally unsuitable for runtime performance in Unity, especially on mobile.

The Problem

Most LINQ operations (.Where(), .Select(), .OrderBy(), .ToList()) allocate memory on the heap. When used inside a frequently called method like Update(), these allocations trigger the Garbage Collector, leading to framerate “hiccups” and stuttering.

void Update() 
{
    // ❌ LINQ allocates an iterator/collection every frame!
    var activeEnemies = allEnemies.Where(e => e.IsActive).ToList(); 
}

Scanner Detection

Code Hygienist Pro identifies usage of common LINQ methods within performance-sensitive scopes.

• High Severity: Flagged as a “Critical” issue for Mobile profiles.
• Context Awareness: The scanner specifically looks for .Select, .Where, .Any, .Count and other enumerable extensions inside Update, FixedUpdate, and LateUpdate.

Best Practice

• Cache results: Perform the query once in Start() or when the data changes, and store the result.
• Use simple loops: Use a standard foreach or for loop with a pre-allocated list to filter data without new allocations.