概要

using System.Linq;
using UnityEngine;

public class Example : MonoBehaviour
{
    private static string[] m_list =
    {
        "フシギダネ",
        "フシギソウ",
        "フシギバナ",
    };

    private void Update()
    {
        var name = "ピカチュウ";

        var result = m_list.Where( c => c == name );
    }
}

通常の LINQ をそのまま使用すると

f:id:baba_s:20191224120913p:plain

184 B の GC Alloc が発生しますが

using System;
using System.Collections.Generic;
using UnityEngine;

public class Example : MonoBehaviour
{
    private static string[] m_list =
    {
        "フシギダネ",
        "フシギソウ",
        "フシギバナ",
    };

    private void Update()
    {
        var name = "ピカチュウ";

        var result = m_list.WhereNotAlloc( ( c, value ) => c == value, name );
    }
}

public static class EnumerableExt
{
    public static IEnumerable<T> WhereNotAlloc<T, TValue>
    (
        this IEnumerable<T>   self,
        Func<T, TValue, bool> predicate,
        TValue                value
    )
    {
        foreach ( var n in self )
        {
            if ( predicate( n, value ) )
            {
                yield return n;
            }
        }
    }
}