Question

我有以下单词列表：

List<string> words = new List<string>();
words.Add("abet");
words.Add("abbots"); //<---Return this
words.Add("abrupt");
words.Add("abduct");
words.Add("abnats"); //<--return this.
words.Add("acmatic");

我想返回6个字母的所有单词，以字母“a”开头，并且“t”作为第5个字母，结果应该返回单词“abbots”和“abnats”。

var result = from w in words
             where w.StartsWith("a") && //where ????

我需要添加什么条款来满足第5个字母的't'要求？

Answer 1

var result = from w in words
             where w.Length == 6 && w.StartsWith("a") && w[4] == 't'
             select w;

Answer 2

您可以使用索引器：

where w.StartsWith("a") && w.Length > 5 && w[4] == 't'

如果没有Length检查，这将为较小的单词抛出异常。

请记住，索引器是从零开始的。

Answer 3

// Now return all words of 6 letters that begin with letter "a" and has "t" as
// the 5th letter. The result should return the words "abbots" and "abnats".

var result = words.Where(w => 
    // begin with letter 'a'
    w.StartsWith("a") &&
    // words of 6 letters
    (w.Length == 6) &&
    // 't' as the 5th letter
    w[4].Equals('t'));

Answer 4

我测试了以下代码，它给出了正确的结果：

var result = from w in words
             where w.StartsWith("a") && w.Length == 6 && w.Substring(4, 1) == "t"
             select w;

Answer 5

在回答修改后的问题时，如果要查看最后两个字母，可以使用EndWith方法或指定要检查的索引。正如SLaks指出的那样，如果你使用索引，那么你还必须检查长度，以确保较小的单词不会导致问题。

List<string> words = new List<string>();
words.Add("abet");
words.Add("abbots"); //<---Return this
words.Add("abrupt");
words.Add("abduct");
words.Add("abnats"); //<--return this.
words.Add("acmatic");

var result1 = from word in words
              where word.Length == 6 && word.StartsWith("a") && word.EndsWith("ts")
              select word;

var result2 = from word in words
              where word.Length == 6 && word.StartsWith("a") && word[4] == 't' && word[5] == 's'
              select word;

如何返回以某些字符开头和结尾的所有单词？

5 个答案: