Question: Please follow the instructions using Python and the provided code, thank you! Add the method __eq__ to the Array class. Python runs this method when
Please follow the instructions using Python and the provided code, thank you!
Add the method __eq__ to the Array class. Python runs this method when an Array object appears as the left operand of the == operator. The method returns True if its argument is:
- also an Array,
- has the same logical size as the left operand,
- and the pair of items at each logical position in the two arrays are equal.
Otherwise, the method returns False. A main() has been provided to test the implementation of the __eq__ method.
Provided Code:
class Array(object):
"""Represents an array."""
def __init__(self, capacity, fillValue = None):
"""Capacity is the static size of the array.
fillValue is placed at each position."""
self.items = list()
self.logicalSize = 0
# Track the capacity and fill value for adjustments later
self.capacity = capacity
self.fillValue = fillValue
for count in range(capacity):
self.items.append(fillValue)
def __len__(self):
"""-> The capacity of the array."""
return len(self.items)
def __str__(self):
"""-> The string representation of the array."""
return str(self.items)
def __iter__(self):
"""Supports traversal with a for loop."""
return iter(self.items)
def __getitem__(self, index):
"""Subscript operator for access at index.
Precondition: 0 <= index < size()"""
if index < 0 or index >= self.size():
raise IndexError("Array index out of bounds")
return self.items[index]
def __setitem__(self, index, newItem):
"""Subscript operator for replacement at index.
Precondition: 0 <= index < size()"""
if index < 0 or index >= self.size():
raise IndexError("Array index out of bounds")
self.items[index] = newItem
def size(self):
"""-> The number of items in the array."""
return self.logicalSize
def grow(self):
"""Increases the physical size of the array if necessary."""
# Double the physical size if no more room for items
# and add the fillValue to the new cells in the underlying list
for count in range(len(self)):
self.items.append(self.fillValue)
def shrink(self):
"""Decreases the physical size of the array if necessary."""
# Shrink the size by half but not below the default capacity
# and remove those garbage cells from the underlying list
newSize = max(self.capacity, len(self) // 2)
for count in range(len(self) - newSize):
self.items.pop()
def insert(self, index, newItem):
"""Inserts item at index in the array."""
if self.size() == len(self):
self.grow()
if index >= self.size():
self.items[self.size()] = newItem
else:
index = max(index, 0)
# Shift items down by one position
for i in range(self.size(), index, -1):
self.items[i] = self.items[i - 1]
# Add new item and increment logical size
self.items[index] = newItem
self.logicalSize += 1
def pop(self, index):
"""Removes and returns item at index in the array.
Precondition: 0 <= index < size()"""
if index < 0 or index >= self.size():
raise IndexError("Array index out of bounds")
itemToReturn = self.items[index]
# Shift items up by one position
for i in range(index, self.size() - 1):
self.items[i] = self.items[i + 1]
# Reset empty slot to fill value
self.items[self.size() - 1] = self.fillValue
self.logicalSize -= 1
if self.size() <= len(self) // 4 and len(self) > self.capacity:
self.shrink()
return itemToReturn
def main():
"""Test code for modified Array class."""
a = Array(5)
for item in range(4):
a.insert(0, item)
b = a
c = Array(5)
for item in range(4):
c.insert(0, item)
print("True:", a == b)
print("True:", a is b)
print("True:", a == c)
print("False:", a is c)
c.insert(10, 10)
print("False:", a == c)
c.pop(c.size() - 1)
c[2] = 6
print("False:", a == c)
d = []
print("False:", a == d)
if __name__ == "__main__":
main()
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