Python Stack and Calculator Implementation Assignment

# HW3 # REMINDER: The work in this assignment must be your own original work and must be completed alone. class Node: def __init__(self, value): self.value = value self.next = None def __str__(self): return "Node({})".format(self.value) __repr__ = __str__ #=============================================== Part I ============================================== class Stack: ''' >>> x=Stack() >>> x.pop() >>> x.push(2) >>> x.push(4) >>> x.push(6) >>> x Top:Node(6) Stack: 6 4 2 >>> x.pop() 6 >>> x Top:Node(4) Stack: 4 2 >>> len(x) 2 >>> x.peek() 4 ''' def __init__(self): self.top = None def __str__(self): temp=self.top out=[] while temp: out.append(str(temp.value)) temp=temp.next out='\n'.join(out) return ('Top:{}\nStack:\n{}'.format(self.top,out)) __repr__=__str__ def isEmpty(self):

# YOUR CODE STARTS HERE if self.__len__() != 0: return False else: return True def __len__(self): # YOUR CODE STARTS HERE x = self.top count = 0 while x != None: x = x.next count += 1 return count def push(self,value): # YOUR CODE STARTS HERE x = self.top newNode = Node(value) if self.isEmpty()== False: newNode.next = x self.top = newNode else: self.top = newNode def pop(self): # YOUR CODE STARTS HERE if self.isEmpty(): return None else: x_value = self.top.value self.top = self.top.next return x_value def peek(self): # YOUR CODE STARTS HERE if self.isEmpty(): return None else: return self.top.value #=============================================== Part II ============================================== class Calculator: def __init__(self): self.__expr = None @property def getExpr(self): return self.__expr def setExpr(self, new_expr): if isinstance(new_expr, str): self.__expr=new_expr

else: print('setExpr error: Invalid expression') return None def _isNumber(self, txt): ''' >>> x=Calculator() >>> x._isNumber(' 2.560 ') True >>> x._isNumber('7 56') False >>> x._isNumber('2.56p') False ''' # YOUR CODE STARTS HERE try: txt = float(txt) return True except: return False def tocheckInvalidity(self, txt): x = txt lst1 = ['^', '*', '/', '+', '-'] lst2 = ['(', ')'] if x[-1] in lst1: return False for i in x: if (i not in lst1) and (self._isNumber(i)!=True) and (i not in lst2): return False count = 0 for i in x: if i == ')': count -= 1 elif i == '(': count +=1 if count != 0: return False count1 = 0 count2 = 1 for i in range(1, len(x)): if (self._isNumber(x[count1]) == True) and (self._isNumber(x[count2]) == True) or (self._isNumber(x[count1]) == True) and (x[count2] == '('): return False elif (x[count1] in lst1) and (x[count2] in lst1) or (x[count1] == ')') and (x[count2] == '(') : return False count1 =count1+1 count2 = count2+1 def _getPostfix(self, txt): ''' Required: _getPostfix must create and use a Stack for expression processing >>> x=Calculator() >>> x._getPostfix(' 2 ^ 4')

Your preview ends here

Eager to read complete document? Join bartleby learn and gain access to the full version

Access to all documents
Unlimited textbook solutions
24/7 expert homework help

'2.0 4.0 ^' >>> x._getPostfix(' 2 ') '2.0' >>> x._getPostfix('2.1 * 5 + 3 ^ 2 + 1 + 4.45') '2.1 5.0 * 3.0 2.0 ^ + 1.0 + 4.45 +' >>> x._getPostfix('2*5.34+3^2+1+4') '2.0 5.34 * 3.0 2.0 ^ + 1.0 + 4.0 +' >>> x._getPostfix('2.1 * 5 + 3 ^ 2 + 1 + 4') '2.1 5.0 * 3.0 2.0 ^ + 1.0 + 4.0 +' >>> x._getPostfix('( .5 )') '0.5' >>> x._getPostfix ('( ( 2 ) )') '2.0' >>> x._getPostfix ('2 * ( ( 5 +-3 ) ^ 2 + (1 + 4 ))') '2.0 5.0 -3.0 + 2.0 ^ 1.0 4.0 + + *' >>> x._getPostfix ('(2 * ( ( 5 + 3) ^ 2 + (1 + 4 )))') '2.0 5.0 3.0 + 2.0 ^ 1.0 4.0 + + *' >>> x._getPostfix ('((2 *((5 + 3 ) ^ 2 + (1 +4 )) ))') '2.0 5.0 3.0 + 2.0 ^ 1.0 4.0 + + *' >>> x._getPostfix('2* ( -5 + 3 ) ^2+ ( 1 +4 )') '2.0 -5.0 3.0 + 2.0 ^ * 1.0 4.0 + +' # In invalid expressions, you might print an error message, adjust doctest accordingly # If you are veryfing the expression in calculate before passing to postfix, this cases are not necessary >>> x._getPostfix('2 * 5 + 3 ^ + -2 + 1 + 4') >>> x._getPostfix(' 2 * 5 + 3 ^ * 2 + 1 + 4') >>> x._getPostfix('2 5') >>> x._getPostfix('25 +') >>> x._getPostfix(' 2 * ( 5 + 3 ) ^ 2 + ( 1 +4 ') >>> x._getPostfix(' 2 * ( 5 + 3 ) ^ 2 + ) 1 + 4 (') >>> x._getPostfix('2 * 5% + 3 ^ + -2 +1 +4') ''' # YOUR CODE STARTS HERE postfixStack = Stack() # method must use postfixStack to compute the postfix expression txt = txt.strip(' ') txt=txt+' ' #to avoid going out of bounds txtmod="" #to store the output with spaces at right places lst1= ['^', '*', '/', '+', '-'] for i in range(len(txt)-1): if (txt[i]=='-' and self._isNumber(txt[i+1]) and txt[i-1] in lst1): txtmod=txtmod+" "+str(txt[i]) elif (txt[i]=='-' and self._isNumber(txt[i+1]) and self._isNumber(txt[i-1])== False): txtmod=txtmod+str(txt[i]) elif (self._isNumber(txt[i]) and (txt[i+1])=='.') or (txt[i] =='.' and self._isNumber(txt[i+1])) or (self._isNumber(txt[i]) and self._isNumber(txt[i+1])): txtmod=txtmod+str(txt[i]) elif (txt[i] =='(' and (txt[i+1])=='(') or (txt[i] ==')' and (txt[i+1])==')') or (self._isNumber(txt[i]) and (txt[i+1])==')')or (txt[i]=='(' and

self._isNumber(txt[i+1])): txtmod=txtmod+str(txt[i])+" " elif (txt[i] in lst1 and self._isNumber(txt[i+1])) or (txt[i] in lst1 and (txt[i+1])=='(') or (self._isNumber(txt[i]) and (txt[i+1]) in lst1): txtmod=txtmod+str(txt[i])+" " else: txtmod=txtmod+str(txt[i]) txtmod=txtmod.strip(' ') txtmod = txtmod.split(' ') txtmod2=[] #to store the output without unnecessary spaces for i in txtmod: if i !="": txtmod2.append(i) txt=txtmod2 if self.tocheckInvalidity(txt) != False: postfix = [] precedence = {'(':5, ')':5, '^':4, '*':3, '/':3, '+':2, '-':2} for i in range(0, len(txt)): next = txt[i] if self._isNumber(next) == True: postfix.append(str(float(next))) else: if postfixStack.isEmpty() != True: if next == '(': postfixStack.push(next) elif next == ')': while postfixStack.peek()!='(': postfix.append(postfixStack.pop()) postfixStack.pop() else: check = True while (postfixStack.isEmpty()!=True) and (precedence[next] <= precedence[postfixStack.peek()]) and check == True: if (precedence[next] == 4 and precedence[postfixStack.peek()] == 4) or postfixStack.peek() == '(': check = False else: postfix.append(postfixStack.pop()) postfixStack.push(next) else: postfixStack.push(next) while postfixStack.isEmpty() == False: if postfixStack.peek() != '(': postfix.append(postfixStack.pop()) else: postfixStack.pop()

return (' '.join(postfix)) else: return None @property def calculate(self): ''' calculate must call _getPostfix calculate must create and use a Stack to compute the final result as shown in the video lecture >>> x=Calculator() >>> x.setExpr('4 + 3 - 2') >>> x.calculate 5.0 >>> x.setExpr('-2 + 3.5') >>> x.calculate 1.5 >>> x.setExpr(' 4 + 3.65 - 2 / 2') >>> x.calculate 6.65 >>> x.setExpr('23 / 12 - 223 + 5.25 * 4 * 3423') >>> x.calculate 71661.91666666667 >>> x.setExpr('2-3*4') >>> x.calculate -10.0 >>> x.setExpr('7^2^3') >>> x.calculate 5764801.0 >>> x.setExpr(' 3 * ((( 10 - 2*3 )) )') >>> x.calculate 12.0 >>> x.setExpr(' 8 / 4 * (3 - 2.45 * ( 4 - 2 ^ 3 ) ) + 3') >>> x.calculate 28.6 >>> x.setExpr('2 * ( 4 + 2 * ( 5 - 3 ^ 2 ) + 1 ) + 4') >>> x.calculate -2.0 >>> x.setExpr(' 2.5 + 3 * (2 + ( 3.0) * ( 5^2-2 * 3 ^ ( 2 ) ) * ( 4 ) ) * ( 2 / 8 + 2 * ( 3 - 1 /3 ) ) - 2 / 3^ 2') >>> x.calculate 1442.7777777777778 # In invalid expressions, you might print an error message, but code must return None, adjust doctest accordingly >>> x.setExpr(" 4 ++ 3+ 2") >>> x.calculate >>> x.setExpr("4 3 +2") >>> x.calculate >>> x.setExpr('( 2 ) * 10 - 3 *( 2 - 3 * 2 ) )') >>> x.calculate >>> x.setExpr('( 2 ) * 10 - 3 * / ( 2 - 3 * 2 )') >>> x.calculate >>> x.setExpr(' ) 2 ( *10 - 3 * ( 2 - 3 * 2 ) ') >>> x.calculate

Your preview ends here

Eager to read complete document? Join bartleby learn and gain access to the full version

Access to all documents
Unlimited textbook solutions
24/7 expert homework help

>>> x.setExpr('( 3.5 ) ( 15 )') >>> x.calculate >>> x.setExpr('3 ( 5) - 15 + 85 ( 12)') >>> x.calculate >>> x.setExpr("( -2/6) + ( 5 ( ( 9.4 )))") >>> x.calculate ''' if not isinstance(self.__expr,str) or len(self.__expr)<=0: print("Argument error in calculate") return None calcStack = Stack() # method must use calcStack to compute the expression # YOUR CODE STARTS HERE if not isinstance(self.__expr,str) or len(self.__expr)<=0: print("Argument error in calculate") return None calcStack = Stack() # method must use calcStack to compute the expression # YOUR CODE STARTS HERE postfix_exp = self._getPostfix(self.__expr) if postfix_exp != None: postfix_exp = postfix_exp.split(' ') operators = ['/','*','+','-','^'] for i in range(0, len(postfix_exp)): current = postfix_exp[i] if self._isNumber(current) == True: calcStack.push(float(current)) else: x = calcStack.pop() y = calcStack.pop() if current == '^': ans = y**x elif current == '/': ans = y/x elif current == '*': ans = y*x elif current == '+': ans = y+x elif current == '-': ans = y-x calcStack.push((ans)) return (float(calcStack.pop())) else: return None #=============================================== Part III ==============================================

class AdvancedCalculator: ''' >>> C = AdvancedCalculator() >>> C.states == {} True >>> C.setExpression('a = 5;b = 7 + a;a = 7;c = a + b;c = a * 0;return c') >>> C.calculateExpressions() == {'a = 5': {'a': 5.0}, 'b = 7 + a': {'a': 5.0, 'b': 12.0}, 'a = 7': {'a': 7.0, 'b': 12.0}, 'c = a + b': {'a': 7.0, 'b': 12.0, 'c': 19.0}, 'c = a * 0': {'a': 7.0, 'b': 12.0, 'c': 0.0}, '_return_': 0.0} True >>> C.states == {'a': 7.0, 'b': 12.0, 'c': 0.0} True >>> C.setExpression('x1 = 5;x2 = 7 * ( x1 - 1 );x1 = x2 - x1;return x2 + x1 ^ 3') >>> C.states == {} True >>> C.calculateExpressions() == {'x1 = 5': {'x1': 5.0}, 'x2 = 7 * ( x1 - 1 )': {'x1': 5.0, 'x2': 28.0}, 'x1 = x2 - x1': {'x1': 23.0, 'x2': 28.0}, '_return_': 12195.0} True >>> print(C.calculateExpressions()) {'x1 = 5': {'x1': 5.0}, 'x2 = 7 * ( x1 - 1 )': {'x1': 5.0, 'x2': 28.0}, 'x1 = x2 - x1': {'x1': 23.0, 'x2': 28.0}, '_return_': 12195.0} >>> C.states == {'x1': 23.0, 'x2': 28.0} True >>> C.setExpression('x1 = 5 * 5 + 97;x2 = 7 * ( x1 / 2 );x1 = x2 * 7 / x1;return x1 * ( x2 - 5 )') >>> C.calculateExpressions() == {'x1 = 5 * 5 + 97': {'x1': 122.0}, 'x2 = 7 * ( x1 / 2 )': {'x1': 122.0, 'x2': 427.0}, 'x1 = x2 * 7 / x1': {'x1': 24.5, 'x2': 427.0}, '_return_': 10339.0} True >>> C.states == {'x1': 24.5, 'x2': 427.0} True >>> C.setExpression('A = 1;B = A + 9;C = A + B;A = 20;D = A + B + C;return D - A') >>> C.calculateExpressions() == {'A = 1': {'A': 1.0}, 'B = A + 9': {'A': 1.0, 'B': 10.0}, 'C = A + B': {'A': 1.0, 'B': 10.0, 'C': 11.0}, 'A = 20': {'A': 20.0, 'B': 10.0, 'C': 11.0}, 'D = A + B + C': {'A': 20.0, 'B': 10.0, 'C': 11.0, 'D': 41.0}, '_return_': 21.0} True >>> C.states == {'A': 20.0, 'B': 10.0, 'C': 11.0, 'D': 41.0} True >>> C.setExpression('A = 1;B = A + 9;2C = A + B;A = 20;D = A + B + C;return D + A') >>> C.calculateExpressions() is None True >>> C.states == {} True ''' def __init__(self): self.expressions = '' self.states = {} def setExpression(self, expression): self.expressions = expression self.states = {} def _isVariable(self, word):

''' >>> C = AdvancedCalculator() >>> C._isVariable('volume') True >>> C._isVariable('4volume') False >>> C._isVariable('volume2') True >>> C._isVariable('vol%2') False ''' # YOUR CODE STARTS HERE if (word[0].isalpha() == True) and (word.isalnum() == True): return True else: return False def _replaceVariables(self, expr): ''' >>> C = AdvancedCalculator() >>> C.states = {'x1': 23.0, 'x2': 28.0} >>> C._replaceVariables('1') '1' >>> C._replaceVariables('105 + x') >>> C._replaceVariables('7 * ( x1 - 1 )') '7 * ( 23.0 - 1 )' >>> C._replaceVariables('x2 - x1') '28.0 - 23.0' ''' # YOUR CODE STARTS HERE x = expr.split(" ") check = True for i in range(0, len(x)): if self._isVariable(x[i]) == True: if x[i] in self.states: x[i] = str(self.states[x[i]]) else: check = False if check == True: return " ".join(x) def calculateExpressions(self): self.states = {} calcObj = Calculator() # method must use calcObj to compute each expression # YOUR CODE STARTS HERE output = {} exp = self.expressions.split(';') check = False for i in exp: if "=" in i: equation = i.split(" = ") numerical = self._replaceVariables(equation[1]) if numerical != None: calcObj.setExpr(numerical)

Your preview ends here

Eager to read complete document? Join bartleby learn and gain access to the full version

Access to all documents
Unlimited textbook solutions
24/7 expert homework help

self.states[equation[0]] = calcObj.calculate output[i] = self.states.copy() else: self.states = {} return None if "return" in i: a = i.split()[1:] b = " ".join(a) c = self._replaceVariables(b) if c != None: calcObj.setExpr(c) d = calcObj.calculate output["_return_"] = d check = True else: self.states = {} return None if len(output) != 0 and check == True: return output else: return None if __name__=='__main__': import doctest doctest.testmod() # OR #doctest.run_docstring_examples(AdvancedCalculator, globals(), name='HW3',verbose=True)

HW3FINALBEST

Related Documents