将文本格式化为 Pascal 或 Camel 大小写的算法

Question

Using this question作为基础，有一个算法或编码示例可以将一些文本更改为 Pascal 或 Camel 大小写。

例如:

mynameisfred

成为

Camel: myNameIsFred
Pascal: MyNameIsFred

Answer 1

我在 http://www.perlmonks.org/?node_id=336331 发现了一个线程，一群 Perl 家伙在争论这个问题。 .

我希望这不是对这个问题的无法回答，但我会说你有一点问题，因为它是一个非常开放的算法，可能会有很多“失误” ' 以及命中率。例如，假设您输入了:-

camelCase("hithisisatest");

输出可能是:-

"hiThisIsATest"

或者:-

"hitHisIsATest"

算法无法知道更喜欢哪个。您可以添加一些额外的代码来指定您更喜欢更常用的单词，但会再次出现遗漏(Peter Norvig 在 http://norvig.com/spell-correct.html 上写了一个非常小的拼写校正器，可能有助于算法，如果 C# 是你的语言，我写了一个 C# implementation。

我同意 Mark 的观点，你最好有一个接受分隔输入的算法，即 this_is_a_test 并转换它。这很容易实现，即在伪代码中:-

SetPhraseCase(phrase, CamelOrPascal):
    if no delimiters
     if camelCase
      return lowerFirstLetter(phrase)
     else
      return capitaliseFirstLetter(phrase)
    words = splitOnDelimiter(phrase)
    if camelCase 
      ret = lowerFirstLetter(first word) 
     else
      ret = capitaliseFirstLetter(first word)
    for i in 2 to len(words): ret += capitaliseFirstLetter(words[i])
    return ret

capitaliseFirstLetter(word):
    if len(word) <= 1 return upper(word)
    return upper(word[0]) + word[1..len(word)]

lowerFirstLetter(word):
    if len(word) <= 1 return lower(word)
    return lower(word[0]) + word[1..len(word)]

如果您愿意，您也可以用适当的大小写算法替换我的 capitaliseFirstLetter() 函数。

上述算法的 C# 实现如下(带有测试工具的完整控制台程序):-

using System;

class Program {
  static void Main(string[] args) {

    var caseAlgorithm = new CaseAlgorithm('_');

    while (true) {
      string input = Console.ReadLine();

      if (string.IsNullOrEmpty(input)) return;

      Console.WriteLine("Input '{0}' in camel case: '{1}', pascal case: '{2}'",
        input,
        caseAlgorithm.SetPhraseCase(input, CaseAlgorithm.CaseMode.CamelCase),
        caseAlgorithm.SetPhraseCase(input, CaseAlgorithm.CaseMode.PascalCase));
    }
  }
}

public class CaseAlgorithm {

  public enum CaseMode { PascalCase, CamelCase }

  private char delimiterChar;

  public CaseAlgorithm(char inDelimiterChar) {
    delimiterChar = inDelimiterChar;
  }

  public string SetPhraseCase(string phrase, CaseMode caseMode) {

    // You might want to do some sanity checks here like making sure
    // there's no invalid characters, etc.

    if (string.IsNullOrEmpty(phrase)) return phrase;

    // .Split() will simply return a string[] of size 1 if no delimiter present so
    // no need to explicitly check this.
    var words = phrase.Split(delimiterChar);

    // Set first word accordingly.
    string ret = setWordCase(words[0], caseMode);

    // If there are other words, set them all to pascal case.
    if (words.Length > 1) {
      for (int i = 1; i < words.Length; ++i)
        ret += setWordCase(words[i], CaseMode.PascalCase);
    }

    return ret;
  }

  private string setWordCase(string word, CaseMode caseMode) {
    switch (caseMode) {
      case CaseMode.CamelCase:
        return lowerFirstLetter(word);
      case CaseMode.PascalCase:
        return capitaliseFirstLetter(word);
      default:
        throw new NotImplementedException(
          string.Format("Case mode '{0}' is not recognised.", caseMode.ToString()));
    }
  }

  private string lowerFirstLetter(string word) {
    return char.ToLower(word[0]) + word.Substring(1);
  }

  private string capitaliseFirstLetter(string word) {
    return char.ToUpper(word[0]) + word.Substring(1);
  }
}