找出字符在串中的所有出现

在循环中使用IndexOf来确定一个字符出现多少次，并明确分别出现在串中的什位置。

1 使用ist<int>来保存找到的字符串的位置，最后一个为找到的字符串的总数

public static int[] FindAllOccurrences(char matchChar, string source, int maxMatches, bool caseSensitivity) { List<int> occurrences = new List<int>(); int foundPos = -1; //找到字符的位置，-1表示未找到 int numberFound = 0; //找到符合条件的字符的个数 int startPos = 0; char tempMatchChar = matchChar; string tempSource = source; //如果忽略大小写则全部转换为大写 if (!caseSensitivity) { tempMatchChar = char.ToUpper(matchChar); tempSource = source.ToUpper(); } do { foundPos = tempSource.IndexOf(tempMatchChar, startPos); //如果找到符合条件的字符 if (foundPos > -1) { startPos = foundPos + 1; numberFound++; if (maxMatches > -1 && numberFound > maxMatches) { break; } else { occurrences.Add(foundPos); } } } while (foundPos > -1); //最后一位为找到的字符总数 occurrences.Add(numberFound); return (occurrences.ToArray()); } //重载函数,找出所有符合条件字符的位置 public static int[] FindAllOccurrences(char matchChar, string source, bool caseSensitivity) { return FindAllOccurrences(matchChar, source, -1, caseSensitivity); } //重载函数，不区分大小写 public static int[] FindAllOccurrences(char matchChar, string source,int maxMatches) { return FindAllOccurrences(matchChar, source, maxMatches , false ); } //重载函数，不区分大小写,匹配全部 public static int[] FindAllOccurrences(char matchChar, string source) { return FindAllOccurrences(matchChar, source, -1, false ); }

2 定义一个类来分别保存字符串的位置和总数

名字没命名好，哈哈，将就着吧

public class PosandValue { int _pos; List<int> _value; public PosandValue(int pos, List<int> value) { _pos = pos; _value = value; } public int Pos { get {return _pos; } } public List<int> Value { get { return _value; } } } public static PosandValue Find(char matchChar, string source, int maxMatches, bool caseSensitivity) { List<int> occurrences = new List<int>(); int foundPos = -1; //找到字符的位置，-1表示未找到 int numberFound = 0; //找到符合条件的字符的个数 int startPos = 0; char tempMatchChar = matchChar; string tempSource = source; //如果忽略大小写则全部转换为大写 if (!caseSensitivity) { tempMatchChar = char.ToUpper(matchChar); tempSource = source.ToUpper(); } do { foundPos = tempSource.IndexOf(tempMatchChar, startPos); //如果找到符合条件的字符 if (foundPos > -1) { startPos = foundPos + 1; numberFound++; if (maxMatches > -1 && numberFound > maxMatches) { break; } else { occurrences.Add(foundPos); } } } while (foundPos > -1); PosandValue PV = new PosandValue(numberFound ,occurrences ); return PV ; }