Question

为什么调用此函数不会打印任何内容？

using System;
using System.Collections.Generic;
using System.Linq;
using System.Globalization;

public class Program
{
    public static void Main()
    {
        Dictionary<string, List<string>> cars = new Dictionary <string, List<string>>() {
                {"importcar",    new List<string>() {"audi", "bmw", "mercedes"}},
                {"domesticcar",  new List<string>() {"chevy", "mustang"}},
                {"truck", new List<string>(){"ford", "gmc", "chevy", "toyota"}}
            };
        var query = cars.Where(x => x.Value.Contains(" CHEVY", new TrimStringComparer())).ToArray();
        for (int i = 0; i < query.Length; i++)
        {
            cars.Remove(query[i].Key);  
        }
        Console.WriteLine(cars.Count); //Or any other logic you need...
    }

}

class TrimStringComparer : IEqualityComparer<String> //Use this instead of StringComparer.InvariantCultureIgnoreCase if you need to Trim() both values in the comparison
{
    public bool Equals(string x, string y)
    {
        return x.Trim().ToLowerInvariant().Equals(y.Trim().ToLowerInvariant());
    }

    public int GetHashCode(string obj)
    {
        return obj.GetHashCode();
    }
}

Answer 1

for已被延迟评估，您的代码中没有任何内容询问以获取for的结果。试试doseq：

(defn test-go-loop []
  (go (doseq [a (cycle [:a :b :c])]
        (println a)
        (<! (timeout 1000)))))

为什么不'for'在'go'里面工作？

1 个答案: