Sum()方法計(jì)算集合中數(shù)字項(xiàng)的總和。
下面的示例演示原始集合上的Sum()方法。
IList<int> intList = new List<int>() { 10, 21, 30, 45, 50, 87 };
var total = intList.Sum();
Console.WriteLine("總計(jì): {0}", total);
var sumOfEvenElements = intList.Sum(i => {
if(i%2 == 0)
return i;
return 0;
});
Console.WriteLine("偶數(shù)元素的總計(jì): {0}", sumOfEvenElements );總計(jì)：243 偶數(shù)元素的總計(jì)：90
下面的示例計(jì)算學(xué)生集合中所有學(xué)生的年齡總和，以及成年學(xué)生的人數(shù)。
IList<Student> studentList = new List<Student>>() {
new Student() { StudentID = 1, StudentName = "John", Age = 13} ,
new Student() { StudentID = 2, StudentName = "Moin", Age = 21 } ,
new Student() { StudentID = 3, StudentName = "Bill", Age = 18 } ,
new Student() { StudentID = 4, StudentName = "Ram" , Age = 20} ,
new Student() { StudentID = 5, StudentName = "Ron" , Age = 15 }
};
var sumOfAge = studentList.Sum(s => s.Age);
Console.WriteLine("學(xué)生年齡總和: {0}", sumOfAge);
var numOfAdults = studentList.Sum(s => {
if(s.Age >= 18)
return 1;
else
return 0;
});
Console.WriteLine("成年學(xué)生人數(shù): {0}", numOfAdults);// 學(xué)生集合
Dim studentList = New List(Of Student) From {
New Student() With {.StudentID = 1, .StudentName = "John", .Age = 13},
New Student() With {.StudentID = 2, .StudentName = "Moin", .Age = 21},
New Student() With {.StudentID = 3, .StudentName = "Bill", .Age = 18},
New Student() With {.StudentID = 4, .StudentName = "Ram", .Age = 20},
New Student() With {.StudentID = 5, .StudentName = "Ron", .Age = 15}
}
Dim sumOfAge = studentList.Sum(Function(s) s.Age)
Console.WriteLine("學(xué)生年齡總和: {0}", sumOfAge)
Dim numOfAdults = studentList.Sum(Function(s)
if(s.Age >= 18)
return 1
else
return 0
end if
end function)
Console.WriteLine("成年學(xué)生人數(shù): {0}", numOfAdults)學(xué)生年齡總和：87 成年學(xué)生人數(shù)：3
C# 查詢語(yǔ)法中不支持Sum運(yùn)算符。
// 學(xué)生集合
Dim studentList = New List(Of Student) From {
New Student() With {.StudentID = 1, .StudentName = "John", .Age = 13},
New Student() With {.StudentID = 2, .StudentName = "Moin", .Age = 21},
New Student() With {.StudentID = 3, .StudentName = "Bill", .Age = 18},
New Student() With {.StudentID = 4, .StudentName = "Ram", .Age = 20},
New Student() With {.StudentID = 5, .StudentName = "Ron", .Age = 15}
}
Dim totalAge = Aggregate st In studentList Into Sum(st.Age)
Console.WriteLine("所有年齡段的總和: {0}", totalAge);所有年齡段的總和：87