def buildparsetree(exp):
plist = exp.split()
pstack = Stack()
tree = BinaryTree('')
pstack.push(tree)
current_tree = tree
for item in plist:
if item == '(':
current_tree.insert_left('')
pstack.push(current_tree)
current_tree = current_tree.get_lc()
elif item not in ['+', '-', '*', '/', ')']:
current_tree.set_root(float(item))
current_tree = pstack.pop()
elif item in ['+', '-', '*', '/']:
current_tree.set_root(item)
current_tree.insert_right('')
pstack.push(current_tree)
current_tree = current_tree.get_rc()
elif item == ')':
current_tree = pstack.pop()
else:
raise ValueError
return tree
def postfix_from(self, infix):
infix = self.__prepare(infix)
prec = {}
prec["^"] = 4
prec["*"] = 3
prec["/"] = 3
prec["+"] = 2
prec["-"] = 2
prec["("] = 1
opStack = Stack()
postfixList = []
tokenList = infix.split()
for token in tokenList:
if self.__is_number(token) or token == "pi" or token == "e":
postfixList.append(token)
elif token == '(':
opStack.push(token)
elif token == ')':
topToken = opStack.pop()
while topToken != '(':
postfixList.append(topToken)
topToken = opStack.pop()
else:
while (not opStack.isEmpty()) and \
(prec[opStack.peek()] >= prec[token]):
postfixList.append(opStack.pop())
opStack.push(token)
while not opStack.isEmpty():
postfixList.append(opStack.pop())
return " ".join(postfixList)
def postfix_converter(infixstring):
op_stack = Stack()
output_list = []
infix_list = infixstring.split(' ')
operators = '*/+-'
for char in infix_list:
if char == '(':
op_stack.push(char)
elif char == ')':
prior_op = op_stack.pop()
while prior_op != '(':
output_list.append(prior_op)
prior_op = op_stack.pop()
elif char in operators:
if op_stack.contains_items() and op_stack.peek() in '*/':
output_list.append(op_stack.pop())
op_stack.push(char)
else:
op_stack.push(char)
else:
output_list.append(char)
while op_stack.contains_items():
output_list.append(op_stack.pop())
return " ".join(output_list)
def revertOrder(a_list):
the_stack = Stack()
the_reverted_cards = []
for i in a_list:
the_stack.push(i)
while not the_stack.is_empty():
the_reverted_cards.append(the_stack.pop())
return the_reverted_cards
def int_to_bin(value):
stack = Stack()
num = int(value)
binary_num = ''
while num > 0:
stack.push(num % 2)
num //= 2
while stack.contains_items():
binary_num += str(stack.pop())
return binary_num
def postfixxer(prefix):
s=Stack()
l=len(prefix)
for i in range(l-1,-1,-1):
if(isOperator(prefix[i])):
temp=s.pop()
temp2=temp+s.pop()+prefix[i]
s.push(temp2)
else:
s.push(prefix[i])
return s.peek()
def infixxer(postfix):
s = Stack()
l = len(postfix)
for i in range(l):
if (isOperator(postfix[i])):
temp = s.pop()
temp2 = '(' + s.pop() + postfix[i] + temp + ')'
s.push(temp2)
else:
s.push(postfix[i])
return s.peek()
def prefixxer(postfix):
s = Stack()
l = len(postfix)
for i in range(l):
if (isOperator(postfix[i])):
temp = ''
temp2 = ''
temp = s.pop()
temp2 = postfix[i] + s.pop() + temp
s.push(temp2)
else:
s.push(postfix[i])
return s.peek()
def base_converter():
stack = Stack()
digits = '0123456789ABCDEF'
num = int(raw_input('Enter a number in base-10 to convert: '))
base = int(raw_input('Enter a base to convert it to: '))
new_num = ''
while num > 0:
stack.push(num % base)
num //= base
while stack.contains_items():
new_num += str(digits[stack.pop()])
print new_num
def postfix_evaluator(statement):
operands_stack = Stack()
statement_list = statement.split(' ')
operators_dict = {'*': operator.mul, '/': operator.div,
'+': operator.add, '-': operator.sub}
for char in statement_list:
if char in operators_dict and operands_stack.size() >= 2:
b = operands_stack.pop()
a = operands_stack.pop()
operands_stack.push(operators_dict[char](a,b))
else:
operands_stack.push(float(char))
return operands_stack.pop()
def paren_checker(string):
stack = Stack()
for char in string:
if char == '(':
stack.push(char)
elif char == ')':
if stack.contains_items():
stack.pop()
else:
return 'Unbalanced'
if stack.contains_items():
return 'Unbalanced'
else:
return 'Balanced'
def Evaluate(self, postfix):
opStack = Stack()
tokenList = postfix.split()
for token in tokenList:
if self.__is_number(token) or token == "pi" or token == "e":
if token == "pi":
token = np.pi
elif token == "e":
token = np.e
opStack.push(float(token))
else:
op2 = opStack.pop()
op1 = opStack.pop()
result = self.__doMath(token, op1, op2)
opStack.push(result)
return opStack.pop()
def general_checker(string):
stack = Stack()
opens = '([{<'
closes = ')]}>'
for char in string:
if char in opens:
stack.push(char)
elif char in closes:
if not stack.contains_items():
return "Stack prematurely empty. Unbalanced."
else:
prior = stack.pop()
return match_checker(char,
prior) # returns Balanced or Unbalanced
if stack.contains_items():
return 'Unbalanced'
else:
return 'Balanced'
############################################## # # Programmer: Stanley Wong # File: StackDriver.py # Description: Python Stack Driver # ############################################## from StackClass import Stack myStack = Stack() myStack.push(22) myStack.push(33) myStack.push(44) myStack.pop() myStack.push(99) myStack.push(55) myStack.push(88) myStack.pop() myStack.push(77) myStack.push(11) myStack.pop() myStack.push(88) myStack.printStack()
"""Qustions. A Python programm to perform various
operations on a stack using Stack Class"""
#Using the Stack Class of Stack.py Program
from StackClass import Stack
# Create empty stack object
s = Stack()
#Display Menu
Choice = 0
while Choice < 5:
print('_______Stack Operation_______')
print('1. Push Element')
print('2. Pop Element')
print('3. Peep Element')
print('4. Search for Element')
print('5. Exit')
Choice = int(input('Enter your Choice:'))
# Perform a task depending on user choice
if Choice == 1:
element = int(input('Enter Element:'))
s.__push__(element)
elif Choice == 2:
element = s.pop()
if element == -1:
print('The Stack Is Empty')
else:
print('Popped element=', element)
elif Choice == 3:
element = s.peep()
print('Topmost Element=', element)
elif Choice == 4:
def __init__(self):
self.stringToCheck = None
self.stringStack = Stack()
self.isPalindrome = False
# This program displays the first 50 prime numbers
# And ses a stack to store the prime numbers
# Import Stack class
from StackClass import Stack
# Create stack to store prime numbers
stack = Stack()
# Define isPrime with num as a parameter
# This function returns True if the number is prime and false is not
def isPrime(num):
for i in range(2, num // 2 + 1):
if num % i == 0:
return False
return True
# Define primeNum function
# Set accumalator name to 'num' with a value of 2
# Create while statement that calls the getSize method from the Stack class
# only if the numbers are below 50
# Create if statement within while statement that if num == 2 or isPrime == True
# then push num to the stack by calling the push method
# Have num increment by 1 so that each number can be checked if isPrime or not
# Print the stack while size of the stack if below 50
def primeNum():
num = 2
while stack.getSize() < 50:
if num == 2 or isPrime(num) == True:
def stackCards(a_list):
the_stack = Stack()
for i in a_list:
the_stack.push(i)
return the_stack
