C#基础学习

连接多个字符串　　

string[] words = { "The", "quick", "brown", "fox", "jumps", "over", "the", "lazy", "dog." };

var unreadablePhrase = string.Concat(words);
System.Console.WriteLine(unreadablePhrase);


var readablePhrase = string.Join(" ", words);
System.Console.WriteLine(readablePhrase);

输出：
Thequickbrownfoxjumpsoverthelazydog.
The quick brown fox jumps over the lazy dog.

　

string[] fruits = { "grape", "passionfruit", "banana", "abcdef", "mango",
                      "orange", "raspberry", "apple", "blueberry" };

var result1 = fruits.OrderBy(fruit => fruit).ThenBy(fruit => fruit.Length);

Console.WriteLine(string.Join(",", result1));
输出：
abcdef,apple,banana,blueberry,grape,mango,orange,passionfruit,raspberry

Console.WriteLine(string.Concat(result1.Select(a=>a+"\r\n")));
输出：
abcdef
apple
banana
blueberry
grape
mango
orange
passionfruit
raspberry

OrderBy:按升序对序列的元素进行排序。

OrderByDescending:使用指定的比较器按降序对序列的元素排序。

 

 ThenBy:按升序对序列中的元素执行后续排序。

ThenByDescending:按降序对序列中的元素执行后续排序。

https://docs.microsoft.com/zh-cn/dotnet/api/system.linq.enumerable?view=net-6.0

 

 

合并数组

 Console.WriteLine(string.Join("-",words.Concat(fruits)));
　　//  使用  words.Union(fruits)  会剔除重复数据项， Concat  会保留重复数据项

输出：
The-quick-brown-fox-jumps-over-the-lazy-dog.-grape-passionfruit-banana-abcdef-mango-orange-raspberry-apple-blueberry

 

 

 对集合排序，并输出

var alist = new Dictionary<string,string>();
alist.Add("001", "asdf");
alist.Add("004", "gewqe");
alist.Add("009", "23fesf");
alist.Add("002", "refa");
alist.Add("005", "ewre");
Console.WriteLine(string.Join(",",alist.OrderBy(a => a.Key).ThenBy(b => b.Value)));

输出：
[001, asdf],[002, refa],[004, gewqe],[005, ewre],[009, 23fesf]

　

 

https://docs.microsoft.com/zh-cn/dotnet/csharp/tutorials