/// <summary>
/// 将逆波兰式转化为可计算的项
/// </summary>
/// <param name="polish">逆波兰式字符串</param>
/// <returns>可计算项目向量</returns>
private List<PolishItem> GetPolishItemList(string polish)
{
List<PolishItem> resVec = new List<PolishItem>();
string[] polishItem = polish.Split(new char[] { ' ' }, StringSplitOptions.RemoveEmptyEntries);
foreach (string item in polishItem)
{
PolishItem poi = null;
Regex floatRegEx = new Regex("^(\\d*\\.)?\\d+$");
// 常数项
//if (item.All((x) => x >= '0' && x <= '9'))
if (floatRegEx.IsMatch(item))
{
double numitem = Convert.ToDouble(item);
poi = new PolishItem()
{
Number = numitem,
Cluster = null,
ItemType = PolishItemType.CONSTANT,
Reference = numitem
};
}
// 字符串
else if (item.StartsWith("\"") && item.EndsWith("\""))
{
string trimItem = item.Substring(1, item.Length - 2);
poi = new PolishItem()
{
Number = 0.0f,
Cluster = trimItem,
ItemType = PolishItemType.STRING,
Reference = trimItem
};
}
// 变量时
else if ((item.StartsWith("&") || item.StartsWith("$")) && item.Length > 1)
{
object varRef = this.Fetch(item);
if (varRef is double)
{
poi = new PolishItem()
{
Number = (double)varRef,
Cluster = null,
ItemType = PolishItemType.VAR_NUM,
Reference = varRef
};
}
else
{
poi = new PolishItem()
{
Number = 0.0f,
Cluster = Convert.ToString(varRef),
ItemType = PolishItemType.VAR_STRING,
Reference = varRef
};
}
}
else if (item == "+")
{
poi = new PolishItem()
{
Number = 0.0f,
Cluster = null,
ItemType = PolishItemType.CAL_PLUS,
Reference = null
};
}
else if (item == "-")
{
poi = new PolishItem()
{
Number = 0.0f,
Cluster = null,
ItemType = PolishItemType.CAL_MINUS,
Reference = null
};
}
else if (item == "*")
{
poi = new PolishItem()
{
Number = 0.0f,
Cluster = null,
ItemType = PolishItemType.CAL_MULTI,
Reference = null
};
}
else if (item == "/")
{
poi = new PolishItem()
{
Number = 0.0f,
Cluster = null,
ItemType = PolishItemType.CAL_DIV,
Reference = null
};
}
else if (item == "!")
{
poi = new PolishItem()
{
Number = 0.0f,
Cluster = null,
ItemType = PolishItemType.CAL_NOT,
Reference = null
};
}
else if (item == "&&")
{
poi = new PolishItem()
{
Number = 0.0f,
Cluster = null,
ItemType = PolishItemType.CAL_ANDAND,
Reference = null
};
}
else if (item == "||")
{
poi = new PolishItem()
{
Number = 0.0f,
Cluster = null,
ItemType = PolishItemType.CAL_OROR,
Reference = null
};
}
else if (item == "<>")
{
poi = new PolishItem()
{
Number = 0.0f,
Cluster = null,
ItemType = PolishItemType.CAL_NOTEQUAL,
Reference = null
};
}
else if (item == "==")
{
poi = new PolishItem()
{
Number = 0.0f,
Cluster = null,
ItemType = PolishItemType.CAL_EQUAL,
Reference = null
};
}
else if (item == ">")
{
poi = new PolishItem()
{
Number = 0.0f,
Cluster = null,
ItemType = PolishItemType.CAL_BIG,
Reference = null
};
}
else if (item == "<")
{
poi = new PolishItem()
{
Number = 0.0f,
Cluster = null,
ItemType = PolishItemType.CAL_SMALL,
Reference = null
};
}
else if (item == ">=")
{
poi = new PolishItem()
{
Number = 0.0f,
Cluster = null,
ItemType = PolishItemType.CAL_BIGEQUAL,
Reference = null
};
}
else if (item == "<=")
{
poi = new PolishItem()
{
Number = 0.0f,
Cluster = null,
ItemType = PolishItemType.CAL_SMALLEQUAL,
Reference = null
};
}
if (poi != null)
{
resVec.Add(poi);
}
}
return resVec;
}
/// <summary>
/// 获取两个polish计算项是否可以进行操作
/// </summary>
/// <param name="p1">操作数1</param>
/// <param name="p2">操作数2</param>
/// <returns>是否可以作为操作符的双目</returns>
public static bool isOperatable(PolishItem p1, PolishItem p2)
{
if (p1.Reference != null && p2.Reference != null && p1.Reference.GetType() == p2.Reference.GetType()) { return true; }
if (p1.ItemType == PolishItemType.CONSTANT && p2.ItemType == PolishItemType.CONSTANT) { return true; }
if (p1.ItemType == PolishItemType.CONSTANT && p2.ItemType == PolishItemType.VAR_NUM) { return true; }
if (p1.ItemType == PolishItemType.VAR_NUM && p2.ItemType == PolishItemType.VAR_NUM) { return true; }
if (p1.ItemType == PolishItemType.VAR_NUM && p2.ItemType == PolishItemType.CONSTANT) { return true; }
if (p1.ItemType == PolishItemType.STRING && p2.ItemType == PolishItemType.STRING) { return true; }
if (p1.ItemType == PolishItemType.STRING && p2.ItemType == PolishItemType.VAR_STRING) { return true; }
if (p1.ItemType == PolishItemType.VAR_STRING && p2.ItemType == PolishItemType.VAR_STRING) { return true; }
if (p1.ItemType == PolishItemType.VAR_STRING && p2.ItemType == PolishItemType.STRING) { return true; }
return false;
}
/// <summary>
/// 计算表达式
/// </summary>
/// <param name="polish">表达式的逆波兰式</param>
/// <returns>计算结果的值（Double/字符串）</returns>
public object CalculatePolish(string polish)
{
List<PolishItem> calcList = this.GetPolishItemList(polish);
if (calcList.Count == 0)
{
return null;
}
Stack<PolishItem> calcStack = new Stack<PolishItem>();
foreach (PolishItem poi in calcList)
{
// 操作数压栈
if (poi.ItemType < PolishItemType.CAL_PLUS)
{
calcStack.Push(poi);
continue;
}
// 下面开始是运算符
if (poi.ItemType == PolishItemType.CAL_NOT && calcStack.Count >= 1)
{
PolishItem peeker = calcStack.Peek();
if (peeker.ItemType == PolishItemType.CONSTANT || peeker.ItemType == PolishItemType.VAR_NUM)
{
calcStack.Pop();
double notres = Math.Abs(peeker.Number) < 1e-15 ? 1.0 : 0.0;
PolishItem np = new PolishItem()
{
Number = notres,
Reference = notres
};
calcStack.Push(np);
continue;
}
else if (peeker.ItemType == PolishItemType.STRING || peeker.ItemType == PolishItemType.VAR_STRING)
{
calcStack.Pop();
double notres = peeker.Cluster == "" ? 1.0 : 0.0;
PolishItem np = new PolishItem()
{
Number = notres,
Reference = notres
};
calcStack.Push(np);
continue;
}
}
if (calcStack.Count >= 2)
{
PolishItem operand2 = calcStack.Pop();
PolishItem operand1 = calcStack.Pop();
if (PolishItem.isOperatable(operand1, operand2) == true)
{
PolishItem newPoi = null;
double tempDouble = 0;
string tempString = "";
switch (poi.ItemType)
{
case PolishItemType.CAL_PLUS:
if (operand1.Reference is string)
{
tempString = (string)operand1.Reference + (string)operand2.Reference;
newPoi = new PolishItem()
{
Cluster = tempString,
Reference = tempString
};
calcStack.Push(newPoi);
}
else
{
tempDouble = (double)operand1.Reference + (double)operand2.Reference;
newPoi = new PolishItem()
{
Number = tempDouble,
Reference = tempDouble
};
calcStack.Push(newPoi);
}
break;
case PolishItemType.CAL_MINUS:
if (operand1.Reference is double)
{
tempDouble = (double)operand1.Reference - (double)operand2.Reference;
newPoi = new PolishItem()
{
Number = tempDouble,
Reference = tempDouble
};
calcStack.Push(newPoi);
}
else
{
throw new Exception("字符串异常操作：减法");
}
break;
case PolishItemType.CAL_MULTI:
if (operand1.Reference is double)
{
tempDouble = (double)operand1.Reference * (double)operand2.Reference;
newPoi = new PolishItem()
{
Number = tempDouble,
Reference = tempDouble
};
calcStack.Push(newPoi);
}
else
{
throw new Exception("字符串异常操作：乘法");
}
break;
case PolishItemType.CAL_DIV:
if (operand1.Reference is double)
{
if (Math.Abs((double)operand2.Reference) < 0)
{
throw new Exception("除零错误");
}
tempDouble = (double)operand1.Reference / (double)operand2.Reference;
newPoi = new PolishItem()
{
Number = tempDouble,
Reference = tempDouble
};
calcStack.Push(newPoi);
}
else
{
throw new Exception("字符串异常操作：除法");
}
break;
case PolishItemType.CAL_ANDAND:
if (operand1.Reference is double)
{
tempDouble = (Math.Abs((double)operand1.Reference) > 0 && Math.Abs((double)operand2.Reference) > 0) ? 1 : 0;
newPoi = new PolishItem()
{
Number = tempDouble,
Reference = tempDouble
};
calcStack.Push(newPoi);
}
else
{
throw new Exception("字符串异常操作：&&");
}
break;
case PolishItemType.CAL_OROR:
if (operand1.Reference is double)
{
tempDouble = (Math.Abs((double)operand1.Reference) > 0 || Math.Abs((double)operand2.Reference) > 0) ? 1 : 0;
newPoi = new PolishItem()
{
Number = tempDouble,
Reference = tempDouble
};
calcStack.Push(newPoi);
}
else
{
throw new Exception("字符串异常操作：||");
}
break;
case PolishItemType.CAL_EQUAL:
if (operand1.Reference is double)
{
tempDouble = (double)operand1.Reference == (double)operand2.Reference ? 1 : 0;
newPoi = new PolishItem()
{
Number = tempDouble,
Reference = tempDouble
};
calcStack.Push(newPoi);
}
else
{
tempDouble = (string)operand1.Reference == (string)operand2.Reference ? 1 : 0;
newPoi = new PolishItem()
{
Number = tempDouble,
Reference = tempDouble
};
calcStack.Push(newPoi);
}
break;
case PolishItemType.CAL_NOTEQUAL:
if (operand1.Reference is double)
{
tempDouble = (double)operand1.Reference != (double)operand2.Reference ? 1 : 0;
newPoi = new PolishItem()
{
Number = tempDouble,
Reference = tempDouble
};
calcStack.Push(newPoi);
}
else
{
tempDouble = (string)operand1.Reference != (string)operand2.Reference ? 1 : 0;
newPoi = new PolishItem()
{
Number = tempDouble,
Reference = tempDouble
};
calcStack.Push(newPoi);
}
break;
case PolishItemType.CAL_BIG:
if (operand1.Reference is double)
{
tempDouble = (double)operand1.Reference > (double)operand2.Reference ? 1 : 0;
newPoi = new PolishItem()
{
Number = tempDouble,
Reference = tempDouble
};
calcStack.Push(newPoi);
}
else
{
tempDouble = String.Compare((string)operand1.Reference, (string)operand2.Reference) > 0 ? 1 : 0;
newPoi = new PolishItem()
{
Number = tempDouble,
Reference = tempDouble
};
calcStack.Push(newPoi);
}
break;
case PolishItemType.CAL_BIGEQUAL:
if (operand1.Reference is double)
{
tempDouble = (double)operand1.Reference >= (double)operand2.Reference ? 1 : 0;
newPoi = new PolishItem()
{
Number = tempDouble,
Reference = tempDouble
};
calcStack.Push(newPoi);
}
else
{
tempDouble = String.Compare((string)operand1.Reference, (string)operand2.Reference) >= 0 ? 1 : 0;
newPoi = new PolishItem()
{
Number = tempDouble,
Reference = tempDouble
};
calcStack.Push(newPoi);
}
break;
case PolishItemType.CAL_SMALL:
if (operand1.Reference is double)
{
tempDouble = (double)operand1.Reference < (double)operand2.Reference ? 1 : 0;
newPoi = new PolishItem()
{
Number = tempDouble,
Reference = tempDouble
};
calcStack.Push(newPoi);
}
else
{
tempDouble = String.Compare((string)operand1.Reference, (string)operand2.Reference) < 0 ? 1 : 0;
newPoi = new PolishItem()
{
Number = tempDouble,
Reference = tempDouble
};
calcStack.Push(newPoi);
}
break;
case PolishItemType.CAL_SMALLEQUAL:
if (operand1.Reference is double)
{
tempDouble = (double)operand1.Reference <= (double)operand2.Reference ? 1 : 0;
newPoi = new PolishItem()
{
Number = tempDouble,
Reference = tempDouble
};
calcStack.Push(newPoi);
}
else
{
tempDouble = String.Compare((string)operand1.Reference, (string)operand2.Reference) <= 0 ? 1 : 0;
newPoi = new PolishItem()
{
Number = tempDouble,
Reference = tempDouble
};
calcStack.Push(newPoi);
}
break;
default:
break;
}
}
}
}
if (calcStack.Count != 1)
{
throw new Exception("表达式有错误");
}
return calcStack.Peek().Reference;
}