「Unity/Csharp/linq」の版間の差分

2020年5月15日 (金) 13:55時点における版

準備

using System.Linq;

配列データの用意

users

User.cs

[Serializable]
public class User
{
    [SerializeField]
    public int age;
    [SerializeField]
    public string name;
}

List<User> users = new List<User>();
users.Add(new User() { age = 10, name = "taro" });
users.Add(new User() { age = 13, name = "jiro" });
users.Add(new User() { age = 12, name = "saburo" });
users.Add(new User() { age = 15, name = "siro" });

scores

Score.cs
[Serializable]
public class Score 
{
    [SerializeField]
    public string yyyymmdd;
    [SerializeField]
    public int missCnt;
    [SerializeField]
    public int finishCnt;
}

List<Score> scores = new List<Score>();
scores.Add(new Score() { yyyymmdd = "20190316", missCnt = 10, finishCnt = 1 });
scores.Add(new Score() { yyyymmdd = "20190315", missCnt = 13, finishCnt = 2 });
scores.Add(new Score() { yyyymmdd = "20190314", missCnt = 12, finishCnt = 3 });
scores.Add(new Score() { yyyymmdd = "20190313", missCnt = 15, finishCnt = 4 });

条件一行だけ（fetchRow)

public ScoreDay FindRowByYyyymmdd(string yyyymmdd)
{
    List<ScoreDay> scores = FindAll();
    return scores.FirstOrDefault(score => score.yyyymmdd == yyyymmdd);
}
// 検索にひっかからないとnullが帰ってくる
ScoreDay score = dao.FindRowByYyyymmdd("201903");
if (score == null) return;

条件複数行（fetchAll)

public IEnumerable<ScoreDay> FindAllByYyyymmdd(string yyyymmdd)
{
    List<ScoreDay> scores = FindAll();
    return scores.Where(score => score.yyyymmdd == yyyymmdd);
}

条件複数行でソート（fetchAll)

public IEnumerable<ScoreDay> FindAllByYyyymmdd(string yyyymmdd)
{
    List<ScoreDay> scores = FindAll();
    return scores.Where(score => score.yyyymmdd == yyyymmdd).OrderByDescending( value => value.age );
}

順序

// 年下順
IOrderedEnumerable<User>   orderedUsers   = users.OrderBy( value => value.age );
// 年上順
IOrderedEnumerable<User>   orderedDescUsers   = users.OrderByDescending( value => value.age );
foreach (User user in orderedUsers) {
    Debug.Log(user.name);
}

参考：https://doruby.jp/users/ino/entries/%E3%80%90C--Unity%E3%80%91LINQ%E3%82%92%E4%BD%BF%E3%81%A3%E3%81%A6%E3%81%BF%E3%81%9F%E3%82%89%E3%81%A8%E3%81%A6%E3%82%82%E3%82%B9%E3%83%9E%E3%83%BC%E3%83%88%E3%81%A0%E3%81%A3%E3%81%9F

取得件数を絞る

List<Score> scores = new List<Score>();
IEnumerable<Score> tmpScores = scores.Skip(0).Take(100);

指定条件だけに絞る

List<ScoreDay> scores = FindAll();
IEnumerable<Score> tmpScores = scores.Where(score => score.sec > 6);
List<Score> scores = tmpScores.ToList();

条件に引っかからなかった時

List<ScoreDay> scores = FindAll();
IEnumerable<Score> tmpScores = scores.Where(score => score.sec > 6);
if (!tmpScores.Any()) {
    return 0;
}

IEnumerableをListへ変換

IEnumerable<Score> tmpScores = //  略・・・
List<Score> scores = tmpScores.ToList());

数値の合計

List<Score> scores = FindAll();
return scores.Sum(record => record.missCnt);

like検索

List<Score> scores = FindAll();
IEnumerable<Score> scores = scores.Where(record => record.yyyymmdd.Contains("201903")); 
// .Contains("/201903/")); // こういうスラッシュはいらない

likeしたあとの合計

IEnumerable<Score> scores = scores.Where(record => record.yyyymmdd.Contains("201903")); 
Debug.Log("sum=" + scores.Sum(record => record.missCnt));

like前方一致

List<Score> scores = FindAll();
IEnumerable<Score> scores = scores.Where(record => record.yyyymmdd.StartsWith("201903"));

like後方一致

List<Score> scores = FindAll();
IEnumerable<Score> scores = scores.Where(record => record.yyyymmdd.EndsWith("0316"));