def test_array_stack():
array_stack = ArrayStack()
# Assert that we start with an empty stack
assert array_stack.is_empty()
with pytest.raises(Empty):
array_stack.top()
# Push a bunch of elements onto the stack
for i in range(10):
array_stack.push(i)
array_stack, top = array_stack.top()
assert top == i
assert len(array_stack) == i + 1
# Pop all the elements off
for i in range(len(array_stack) - 1, -1, -1):
array_stack, val = array_stack.pop()
assert val == i
assert len(array_stack) == i
# Assert we are back to an empty stack
assert array_stack.is_empty()
with pytest.raises(Empty):
array_stack.pop()
def match_paranthesis(paranthesis):
left = '{[(|'
right = '}])|'
stack = ArrayStack()
for s in paranthesis:
if s in left and s not in right:
stack.push(s)
if s in right:
if s not in left:
if stack.is_empty():
return False
else:
if right.index(s) == left.index(stack.top()):
stack.pop()
else:
return False
else:
if stack.is_empty():
stack.push(s)
else:
if s != stack.top():
stack.push(s)
else:
stack.pop()
return stack.is_empty()
def infix_to_postfix(expression):
postfix = []
priority = {'(': 1, '+': 2, '-': 2, '*': 3, '/': 3, '^': 4}
operators = ArrayStack()
for token in expression:
if token in OPERATORS:
# Operators are added to the stack, but first the ones with a
# higher priority are added to the result:
while not operators.is_empty() and priority[token] <= priority[
operators.top()]:
postfix.append(operators.pop())
operators.push(token)
# Left parenthesis are added to the stack:
elif token == '(':
operators.push(token)
# Operators between parenthesis are added from the stack to the result:
elif token == ')':
while operators.top() != '(':
postfix.append(operators.pop())
operators.pop() # Pop the left parentheses from the stack.
# Operands are added to the result:
else:
postfix.append(token)
while not operators.is_empty():
# The remaining operators are added from the stack to the result:
postfix.append(operators.pop())
return postfix
def is_valid_html(raw_html):
"""
Return True if the each opening html tag in the raw_html string has and associated closing html tag.
Parameters
----------
raw_html: str or unicode
The raw html string we need to check for validity
Returns
-------
Boolean
"""
def is_opening_tag(tag):
return not tag.startswith('/')
stack = ArrayStack()
opening_idx = raw_html.find('<')
while opening_idx != -1:
closing_idx = raw_html.find('>', opening_idx + 1)
if closing_idx == -1:
return False
tag = raw_html[opening_idx + 1:closing_idx]
if is_opening_tag(tag):
stack.push(tag)
else:
if stack.is_empty() or stack.top() != tag[1:]:
return False
else:
stack.pop()
opening_idx = raw_html.find('<', closing_idx + 1)
return stack.is_empty()
def cal_simple_expression(exp):
"""只有+-*/四种运算, 运算数为整数, 运算符前后有空格."""
end = '$' # 表达式结束标志, 最低优先级
priority = {end: 0, '+': 1, '-': 1, '*': 2, '/': 2}
operator_func = {'+': add, '-': sub, '*': mul, '/': truediv}
operand = ArrayStack()
operator = ArrayStack()
exp = exp.split()
exp.append(end) # 添加表达式结束标志以计算最终结果
i = 0
while i < len(exp):
e = exp[i]
if e not in priority.keys():
operand.push(int(e))
i += 1
else:
# 高优先级运算符直接push
if operator.is_empty() or priority[e] > priority[operator.top()]:
operator.push(e)
i += 1
# 低优先级运算符在下一次循环时处理
else:
func = operator_func[operator.pop()]
num1 = operand.pop()
num2 = operand.pop()
operand.push(func(num2, num1))
return operand.pop()
def is_matching(expr):
"""
Return True if delimiters in expr match correctly, False otherwise
Parameters
----------
test_str: str or unicode
expression to evaluate parameters correctness
Returns
-------
Boolean
"""
delimiters_map = {'(': ')', '{': '}', '[': ']'}
stack = ArrayStack()
for c in expr:
if c in delimiters_map:
stack.push(c)
elif c in delimiters_map.itervalues():
if stack.is_empty() or delimiters_map[stack.top()] != c:
return False
else:
stack.pop()
return stack.is_empty()
def test_stack(self):
stack = ArrayStack()
assert stack.__repr__() == 'Stack: bottom [] top'
assert stack.is_empty() == True
stack.push(1)
assert stack.is_empty() == False
assert stack.__repr__() == 'Stack: bottom [1] top'
stack.push(2)
assert len(stack) == 2
assert stack.__repr__() == 'Stack: bottom [1,2] top'
assert stack.top() == 2
assert stack.pop() == 2
assert len(stack) == 1
assert stack.__repr__() == 'Stack: bottom [1] top'
assert stack.top() == 1
assert stack.pop() == 1
assert stack.__repr__() == 'Stack: bottom [] top'
with pytest.raises(EmptyError):
stack.top()
with pytest.raises(EmptyError):
stack.pop()
def main():
print("Creating a stack...")
a = ArrayStack()
print("Length of the stack:", len(a))
print("The stack is empty:", a.is_empty())
print()
print("Pushing 10 to the stack...")
a.push(10)
print("The element at the top of the stack is", a.top())
print("Length of the stack:", len(a))
print("The stack is empty:", a.is_empty())
print()
print("Pushing 20 30 40 50 to the stack in this order...")
a.push(20)
a.push(30)
a.push(40)
a.push(50)
print("The element at the top of the stack is", a.top())
print("Length of the stack:", len(a))
print("The stack is empty:", a.is_empty())
print()
print("Popping the stack...")
a.pop()
print("The element at the top of the stack is", a.top())
print("Length of the stack:", len(a))
print("The stack is empty:", a.is_empty())
print()
print("Popping the stack 4 times...")
for i in range(3):
a.pop()
print("The element at the top of the stack is", a.top())
print("Length of the stack:", len(a))
print("The stack is empty:", a.is_empty())
print()
from array_stack import ArrayStack
a = '((()(){([()])}))'
cd = '((({{}})))'
b= '()(()){([()])}'
c=')(()){([()])}'
d='(}'
S=ArrayStack()
list_a = []
for i in a:
if i=='(' or i=='{' or i=='[':
S.push(i)
print("1",S.data)
elif i==')' and S.top()=='(':
S.pop()
print("2",S.data)
elif i=='}' and S.top()=='{':
S.pop()
print("3",S.data)
elif i==']' and S.top()=='[':
S.pop()
print("4",S.data)
print(S.is_empty())
from array_stack import ArrayStack
a = '((()(){([()])}))'
cd = '((({{}})))'
b = '()(()){([()])}'
c = ')(()){([()])}'
d = '(}'
S = ArrayStack()
list_a = []
for i in a:
if i == '(' or i == '{' or i == '[':
S.push(i)
print("1", S.data)
elif i == ')' and S.top() == '(':
S.pop()
print("2", S.data)
elif i == '}' and S.top() == '{':
S.pop()
print("3", S.data)
elif i == ']' and S.top() == '[':
S.pop()
print("4", S.data)
print(S.is_empty())