[英]C# - How to sort a list of strings using last character by ignoring special character if any at the end
下面是我试图实现并能够对其进行排序的逻辑,但需要弄清楚忽略其中的特殊字符
我的逻辑:
最后通过加入〜分隔符作为字符串返回。
List<String> inputLst= new List<String>() { "Bananas!", "Cherry2", "Mango","Apples", "Grape$", "Guava" }; List<String> sortList = new List<String>(); List<String> outputList = new List<String>(); foreach (String str in inputLst) { sortList.Add(new String(str.ToCharArray().Reverse().ToArray())); } sortList.Sort(); foreach (String str in sortList) { outputList.Add(new String(str.ToCharArray().Reverse().ToArray())); } Return String.Join("~", outputList);
我得到的输出是Bananas!~Grape$~Cherry2~Guava~Mango~Apples
预计产量应该是Guava~Grape$~Mango~Bananas!~Apples~Cherry2
任何人都可以建议我优化解决方案,通过忽略特殊字符按最后一个字符排序列表? 在这里我使用了2个字符串反转列表,它能以更有效的方式完成吗? 注意:不使用LINQ请。
有了一点LINQ和Regex,这可以相对简单地实现:
var inputList = new List<string>() { "Bananas!", "Cherry2", "Mango","Apples", "Grape$", "Guava" };
var outputList = inputList.OrderBy(s => new string(Regex.Replace(s, "[^a-zA-Z]", "")
.Reverse()
.ToArray()))
.ToList();
var output = String.Join("~", outputList);
编辑:非LINQ方法:
var inputList = new List<string>() { "Bananas!", "Cherry2", "Mango", "Apples", "Grape$", "Guava" };
inputList.Sort(new ReverseStringComparer());
var output = String.Join("~", inputList);
ReverseStringComparer:
class ReverseStringComparer : IComparer<string>
{
public int Compare(string x, string y)
{
string a = new string(Regex.Replace(x, "[^a-zA-Z]", "").Reverse().ToArray());
string b = new string(Regex.Replace(y, "[^a-zA-Z]", "").Reverse().ToArray());
return a.CompareTo(b);
}
}
解决方案没有正则表达式:
string foo()
{
List<String> inputLst= new List<String>() { "Bananas!", "Cherry2", "Mango","Apples", "Grape$", "Guava" };
inputLst.Sort((l, r) => new string(l.Reverse().SkipWhile( x => !char.IsLetter(x) ).ToArray()).CompareTo( new string(r.Reverse().SkipWhile(x => !char.IsLetter(x)).ToArray()) ) );
return String.Join("~", inputLst);
}
要按照注释中的建议跳过所有非字母字符(而不仅仅是字符串的开头),只需使用Where
而不是SkipWhile
如下所示:
string bar()
{
List<String> inputLst= new List<String>() { "Bananas!", "Cherry2", "Mango","Apples", "Grape$", "Guava" };
inputLst.Sort((l, r) => new string(l.Reverse().Where( x => char.IsLetter(x) ).ToArray()).CompareTo( new string(r.Reverse().Where(x => char.IsLetter(x)).ToArray()) ) );
return String.Join("~", inputLst);
}
请注意, Where
有INVERS逻辑( char.IsLetter(x)
比较SkipWhile
( !char.IsLetter(x)
找到最后一个符号作为字母并按其排序。
var inputList = new List<string>() {
"Bananas!", "Cherry2", "Mango","Apples", "Grape$", "Guava" };
var outputList = inputList.OrderBy(s => s.Last(c => char.IsLetter(c)));
Console.WriteLine(string.Join("~", outputList));
不需要反向。
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