C# 取字符串中间文本 取字符串左边 取字符串右边
好像是第二种效率高一点,取str字符串中123左边的所有字符:第一种Between(str,"","123"),而第二种是Between(str,null,"123")。
public static string Between(string str, string strLeft, string strRight) //取文本中间 { if (str == null || str.Length == 0) return ""; if (strLeft != "") { int indexLeft = str.IndexOf(strLeft);//左边字符串位置 if (indexLeft < 0) return ""; indexLeft = indexLeft + strLeft.Length;//左边字符串长度 if (strRight != "") { int indexRight = str.IndexOf(strRight, indexLeft);//右边字符串位置 if (indexRight < 0) return ""; return str.Substring(indexLeft, indexRight - indexLeft);//indexRight - indexLeft是取中间字符串长度 } else return str.Substring(indexLeft, str.Length - indexLeft);//取字符串右边 } else//取字符串左边 { int indexRight = str.IndexOf(strRight); if (indexRight <= 0) return ""; else return str.Substring(0, indexRight); } }
public static string Between2(string str, string strLeft, string strRight) //取文本中间 { if (str == null || str.Length == 0) return ""; if (strLeft != null) { int indexLeft = str.IndexOf(strLeft);//左边字符串位置 if (indexLeft < 0) return ""; indexLeft = indexLeft + strLeft.Length;//左边字符串长度 if (strRight != null) { int indexRight = str.IndexOf(strRight, indexLeft);//右边字符串位置 if (indexRight < 0) return ""; return str.Substring(indexLeft, indexRight - indexLeft);//indexRight - indexLeft是取中间字符串长度 } else return str.Substring(indexLeft, str.Length - indexLeft);//取字符串右边 } else//取字符串左边 { if (strRight == null) return ""; int indexRight = str.IndexOf(strRight); if (indexRight <= 0) return ""; else return str.Substring(0, indexRight); } }