一、select用法
Linq中的select可以使我們的對List中的每一項(xiàng)進(jìn)行操作，生成新的列表。
int[] array = { 1,5,6,7,6,9,12,2,7,6,33};List<int> l1 = new List<int>(array);var t1 = l1.Select((p)=>p+10);foreach (var item in t1){ Console.WriteLine(item);}
List<Student> stuList = new List<Student>(){ new Student(){ID=1,Name="John",Chinese=92,Math=88,English=92}, new Student(){ID=2,Name="Mary",Chinese=87,Math=94,English=82}, new Student(){ID=3,Name="KangKang",Chinese=89,Math=91,English=96}, new Student(){ID=4,Name="Maria",Chinese=88,Math=65,English=94}, new Student(){ID=5,Name="Ben",Chinese=70,Math=91,English=82},};var t1 = from e in stuList select e.English;foreach (var item in t1){ Console.WriteLine(item);}
二、SelectMany用法
在C# Linq中，SelectMany方法用于將一個集合中的每個元素轉(zhuǎn)換為另一個集合，并將所有轉(zhuǎn)換后的集合合并為一個新集合。List<List<int>> list = new List<List<int>>(){ new List<int>() { 1, 2, 3 }, new List<int>() { 4, 5, 6 }, new List<int>() { 7, 8, 9 }};var result = list.SelectMany(x => x);foreach (var item in result){ Console.WriteLine(item);}
三、where用法
where在Linq中主要進(jìn)行對數(shù)據(jù)篩選，并且生成新的ListList<Student> stuList = new List<Student>(){ new Student(){ID=1,Name="John",Chinese=92,Math=88,English=92}, new Student(){ID=2,Name="Mary",Chinese=87,Math=94,English=82}, new Student(){ID=3,Name="KangKang",Chinese=89,Math=91,English=96}, new Student(){ID=4,Name="Maria",Chinese=88,Math=65,English=94}, new Student(){ID=5,Name="Ben",Chinese=70,Math=91,English=82},};
var t1 = stuList.Where(p => p.English == 88);
// Linq 語句var t1 = from e in stuList where e.English == 82 select e;
需要注意的是Lambda表達(dá)式中不需要select結(jié)尾，但Linq 語句必須是select結(jié)尾否則報錯四、C# linq 將數(shù)組轉(zhuǎn)換為以逗號分隔的字符串string[] array = { "A", "B", "C", "D" };string str = string.Join(",", array);
該文章在 2025/1/13 10:44:31 編輯過
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