在scala中使用正則表達式匹配數學運算

Question

我想匹配在scala中使用匹配的數學運算。因此，該函數將能夠匹配，如「5 + 2」或「LOG10」或任何字符串「10^5」等，但比賽一直未能爲各個類型的表達式

def isValid(expression:String):Boolean={ 

    val number = """((\-|\+)?[0-9]+\.?[0-9])*""" 
    val operation = """([\+,\-,*,/,C,P])""" 
    val functions = """(log|ln|sin|cos|tan|arc sin|arc cos|arc tan|sec|csc|cot)""" 
    val powers = """\^"""+number 

    val arithmeticExpression = (number + operation + number).r 
    val functionExpression = (functions + number).r 
    val powerOperation = (number + powers).r 
    val stringToTest: Regex = ("""(""" +arithmeticExpression+"""|"""+functionExpression+"""|"""+powerOperation+""")""").r 

    expression match { 
     case arithmeticExpression(s) => true 
     case functionExpression(s) => true 
     case powerOperation(s)=>true 
     case _ => false 

    } 
} 


println(isValid("1+4").toString) 

但是如果我匹配對於一般的表情，我得到預期的輸出：

def isValid(expression:String):Boolean={ 
    val number = """(\-|\+)?[0-9]+\.?[0-9]*""" 
    val operation = """[\+,\-,*,/,C,P]""" 
    val functions = """(log|ln|sin|cos|tan|arc sin|arc cos|arc tan|sec|csc|cot)""" 
    val power = """\^"""+number 
    val arithmeticExpression = number+operation+number 
    val functionExpression = functions+number 
    val powerExpression = number+power 

    val validExpression = """(""" +arithmeticExpression+"""|"""+functionExpression+"""|"""+powerExpression+""")""" 
    validExpression.r.findFirstIn(expression) match { 
     case Some(`expression`) => true 
     case None => false 
    } 

Answer 1

你不是在做正確的數字：

scala> arithmeticExpression.findFirstIn("1+4") 
res2: Option[String] = Some(+)      

scala> arithmeticExpression.unapplySeq("1+4") 
res3: Option[List[String]] = None 

scala> arithmeticExpression.unapplySeq("11+14") 
res4: Option[List[String]] = Some(List(11, null, +, 14, null)) 

既然你需要兩個數字。

Answer 2

數字正則表達式中的「（）」影響結果。還需要包裝在（）中。這最終爲我工作。

def isValid(expression:String):Boolean={ 
    val number = """[\-,\+]?[0-9]+\.?[0-9]*""" 
    val operation = """([\+,\-,*,/,C,P])""" 
    val functions = """(log|ln|sin|cos|tan|arc sin|arc cos|arc tan|sec|csc|cot)""" 
    val powers = """(\^)"""+number 
    val arithmeticExpression = (""""""+number + operation + number+"""""").r 
    val functionExpression = (functions + number).r 
    val powerOperation = (number + powers).r 
    val stringToTest: Regex = ("""(""" +arithmeticExpression+"""|"""+functionExpression+"""|"""+powerOperation+""")""").r 

    expression match { 
     case arithmeticExpression(s) => { 
     println("Arithmetic Match") 
     true 
     } 
     case functionExpression(s) => { 
     println("Function Match") 
     true 
     } 
     case powerOperation(s)=>{ 
     println("Power Match") 
     true 
     } 
     case _ => false 

    } 
} 

感謝您的幫助！