使用 LINQ 查找价值最低的产品
本文关键字:LINQ 查找 使用 | 更新日期: 2023-09-27 18:36:20
我正在学习LINQ,我想从以下列表中找到最便宜的产品:
List<Product> products = new List<Product> {
new Product {Name = "Kayak", Price = 275M, ID=1},
new Product {Name = "Lifejacket", Price = 48.95M, ID=2},
new Product {Name = "Soccer ball", Price = 19.50M, ID=3},
};
我想出了以下内容,但不知何故感觉这不是最好的方法:
var cheapest = products.Find(p => p.Price == products.Min(m => m.Price));
你能告诉我实现这一目标的正确方法吗?
你应该使用MinBy
:
public static TSource MinBy<TSource>(
this IEnumerable<TSource> source,
Func<TSource, IComparable> projectionToComparable
) {
using (var e = source.GetEnumerator()) {
if (!e.MoveNext()) {
throw new InvalidOperationException("Sequence is empty.");
}
TSource min = e.Current;
IComparable minProjection = projectionToComparable(e.Current);
while (e.MoveNext()) {
IComparable currentProjection = projectionToComparable(e.Current);
if (currentProjection.CompareTo(minProjection) < 0) {
min = e.Current;
minProjection = currentProjection;
}
}
return min;
}
}
只需将其添加为public static
类中的方法(EnumerableExtensions
?
现在你可以说
var cheapest = products.MinBy(x => x.Price);
或者,您可以简单地对它们进行排序并获取第一个结果,这是假设您在Product
对象而不是Price
值之后; 就像这样。
var cheapestProduct = products.OrderBy(p => p.Price).FirstOrDefault();
var mostExpensiveProduct = products.OrderByDescending(p => p.Price).FirstOrDefault();
您需要先按价格订购,然后选择第一个。
if(products.Any()){
var productWithCheapestPrice = products.OrderBy(p => p.Price).First();
}