def test_peep_from_non_empty_stack_(self):
stack = Stack()
stack.push(5)
self.assertEqual(stack.peek(), 5)
stack.push(10)
self.assertEqual(stack.peek(), 10)
stack.push(19)
self.assertEqual(stack.peek(), 19)
self.assertEqual(stack.items.walk(), [5, 10, 19])
class TestStack(unittest.TestCase):
def setUp(self):
self.data = ["d1", "d2"]
self.s1 = Stack()
self.s2 = Stack(StackNode(self.data[0]))
self.s3 = Stack()
for datum in self.data:
self.s3.push(datum)
def test_Stack__init__(self):
self.assertEqual(self.s1.current, None)
self.assertEqual(self.s1.len, 0)
self.assertEqual(repr(self.s2.current), self.data[0])
self.assertEqual(self.s2.len, 1)
def test_Stack__iter__(self):
for n in self.s1:
self.assertTrue(False)
for s in [self.s2]: #, self.s3]:
for n in s:
self.assertTrue(repr(n) in self.data)
def test_Stack_push(self):
len1 = len(self.s1)
self.s1.push("foo")
self.assertTrue(len(self.s1) - len1 == 1)
self.assertTrue(self.s1.peek() == "foo")
len2 = len(self.s2)
self.s2.push("bar")
self.assertTrue(len(self.s2) - len2 == 1)
self.assertTrue(self.s2.peek() == "bar")
def test_Stack_pop(self):
self.assertTrue(self.s3.pop() == self.data[1])
self.assertTrue(self.s3.pop() == self.data[0])
def test_Stack_peek(self):
self.assertTrue(self.s3.peek() == self.data[1])
self.assertTrue(self.s3.peek() == self.data[1])
def test_Stack_isEmpty(self):
self.assertTrue(self.s1.isEmpty())
self.assertFalse(self.s2.isEmpty())
def test_Stack__len__(self):
self.assertEquals(len(self.s1), 0)
self.assertEquals(len(self.s2), 1)
self.assertEquals(len(self.s3), 2)
def test_Stack__repr__(self):
self.assertEquals(repr(self.s1), '')
self.assertEquals(repr(self.s2), 'd1')
self.assertEquals(repr(self.s3), 'd2 <- d1')
class StackTests(unittest.TestCase):
def setUp(self):
self.stack = Stack()
def tearDown(self):
self.stack = None
def test_push(self):
self.stack.push(10)
self.assertEqual(self.stack.peek(), 10)
self.stack.push(100)
self.assertEqual(self.stack.peek(), 100)
def test_pop(self):
self.stack.push(1)
self.stack.push(2)
self.stack.push(3)
self.stack.push(4)
self.assertEquals(self.stack.pop(), 4)
self.assertEquals(self.stack.pop(), 3)
self.assertEquals(self.stack.pop(), 2)
self.assertEquals(self.stack.pop(), 1)
with self.assertRaises(IndexError):
self.stack.pop()
def test_peek(self):
self.stack.push(1)
self.stack.push(2)
self.stack.push(3)
self.stack.push(4)
self.assertEquals(self.stack.peek(), 4)
self.stack.pop()
self.assertEquals(self.stack.peek(), 3)
self.stack.pop()
self.assertEquals(self.stack.peek(), 2)
self.stack.pop()
self.assertEquals(self.stack.peek(), 1)
self.stack.pop()
with self.assertRaises(IndexError):
self.stack.peek()
def test_reverse(self):
self.stack.push(1)
self.stack.push(2)
self.stack.push(3)
self.stack.push(4)
self.stack.push(5)
self.stack.reverse()
self.assertEqual(self.stack.pop(), 1)
self.assertEqual(self.stack.pop(), 2)
self.assertEqual(self.stack.pop(), 3)
self.assertEqual(self.stack.pop(), 4)
self.assertEqual(self.stack.pop(), 5)
class StackTests(unittest.TestCase):
def setUp(self):
self.stack = Stack()
def tearDown(self):
self.stack = None
def test_push(self):
self.stack.push(10)
self.assertEqual(self.stack.peek(), 10)
self.stack.push(100)
self.assertEqual(self.stack.peek(), 100)
def test_pop(self):
self.stack.push(1)
self.stack.push(2)
self.stack.push(3)
self.stack.push(4)
self.assertEquals(self.stack.pop(), 4)
self.assertEquals(self.stack.pop(), 3)
self.assertEquals(self.stack.pop(), 2)
self.assertEquals(self.stack.pop(), 1)
with self.assertRaises(IndexError):
self.stack.pop()
def test_peek(self):
self.stack.push(1)
self.stack.push(2)
self.stack.push(3)
self.stack.push(4)
self.assertEquals(self.stack.peek(), 4)
self.stack.pop()
self.assertEquals(self.stack.peek(), 3)
self.stack.pop()
self.assertEquals(self.stack.peek(), 2)
self.stack.pop()
self.assertEquals(self.stack.peek(), 1)
self.stack.pop()
with self.assertRaises(IndexError):
self.stack.peek()
def test_reverse(self):
self.stack.push(1)
self.stack.push(2)
self.stack.push(3)
self.stack.push(4)
self.stack.push(5)
self.stack.reverse()
self.assertEqual(self.stack.pop(), 1)
self.assertEqual(self.stack.pop(), 2)
self.assertEqual(self.stack.pop(), 3)
self.assertEqual(self.stack.pop(), 4)
self.assertEqual(self.stack.pop(), 5)
def dfs_stack(self):
result = []
stack = Stack()
stack.push(self)
current_node = stack.peek()
index = 0
while current_node and index < 8:
for node in reversed(current_node.nodes):
stack.push(node)
current_node = stack.peek()
if len(current_node.nodes) == 0:
result.append(current_node.value)
stack.pop()
current_node = stack.peek()
print(result)
index += 1
def dfs_in_order_stack(self):
result = []
stack = Stack()
stack.push(self)
while stack.peek():
current_node = stack.pop()
result.append(current_node.value)
for node in current_node.nodes:
stack.push(node)
return result
def test_stack(self):
elements = [5, 1, 6, 9, 72, 42, 51]
expected_result = elements.copy()
expected_result.reverse()
stack = Stack()
for element in elements:
stack.push(element)
actual_result = []
while stack.peek():
actual_result.append(stack.pop())
self.assertEqual(expected_result, actual_result)
def is_balanced_symbols(string: str):
stack = Stack()
for char in string:
if char in "([{":
stack.push(char)
elif char in "}])":
if stack.isempty():
return False
elif match(stack.peek(), char):
stack.pop()
else:
return False
if stack.isempty():
return True
else:
return False
class PostfixCalculator(object):
def __init__(self, tokens_string=""):
self._tokens_string = tokens_string
self._stack = Stack()
self._result = 0
@property
def tokens(self):
return self._tokens_string
def _tokenize(self):
return self._tokens_string.split()
def _do_operation(self, operator):
# """ This method mimics a switch statement """
rhs = self._stack.pop() # right hand side operand
lhs = self._stack.pop() # left hand side operand
# switch
return {
"+": int(lhs) + int(rhs),
"-": int(lhs) - int(rhs),
"*": int(lhs) * int(rhs),
"/": int(lhs) / int(rhs),
}.get(operator, "unknown operator {}".format(operator))
def calculate(self):
""" Execute postfix algorithm here """
tokens = self._tokenize()
for token in tokens:
try:
self._stack.push(int(token))
except ValueError:
self._stack.push(self._do_operation(token))
# Peek at the top of the stack to get the result
self._result = self._stack.peek()
@property
def result(self):
return self._result
def infix2postfix(infix):
s = Stack()
l = []
linfix = infix.split()
priority = {"*": 3, "/": 3, "+": 2, "-": 2, "(": 1}
for i in linfix:
if i == "(":
s.push(i)
elif i == ")":
t = s.pop()
while not s.is_empty() and t != "(":
l.append(t)
t = s.pop()
elif i in "+-*/":
while not s.is_empty() and priority[s.peek()] >= priority[i]:
l.append(s.pop())
s.push(i)
else:
l.append(i)
while not s.is_empty():
l.append(s.pop())
return " ".join(l)
from stack.stack import Stack from stack.stack import foo stk = Stack() stk.push(1) stk.push(2) stk.pop() stk.push(3) print stk.peek() print stk.size() print foo()
def test_peek_leaves_element_on_stack(list_arg_non_empty):
st = Stack(list_arg_non_empty)
st.peek()
assert st.peek() == list_arg_non_empty[-1]
def test_peep_from_empty_stack(self):
stack = Stack()
self.assertEqual(stack.items.walk(), [])
self.assertIsNone(stack.peek())
from stack.stack import Stack from stack.stack import foo stk = Stack() stk.push(1) stk.push(2) stk.pop() stk.push(3) print stk.peek() print stk.size() print foo()