LinkedList implementation, Python 3

LinkedList implementation

"""
LinkedList implementation

Author: Jayesh Chandrapal
"""
class Node:
    
    __slots__ = "data", "next"
    
    def __init__(self, data, next = None):
        self.data = data
        self.next = next
    
    def __str__(self):
        return '[' + self.data + ']'
    
class LinkedList:
    
    __slots__ = "front", "back", "currentSize"
    
    def __init__(self):
        self.front = None
        self.back = None
        self.currentSize = 0
        
    def prepend(self, item):
        self.front = Node(item, self.front)
        if self.back is None:
            self.back = self.front
        
        self.currentSize += 1
    
    def append(self, item):
        newnode = Node(item)
        
        if self.back is None:
            self.back = newnode
        else:
            self.back.next = newnode
            self.back = newnode
        
        if self.front is None:
            self.front = self.back
            
        self.currentSize += 1
    
    def contains(self, item):
        if self.empty():
            return False
        
        current = self.front
        while current is not None:
            if current.data == item:
                return True
            current = current.next
            
        return False
    
    def remove(self, item):
        if self.empty():
            return False
        
        current = self.front
        previous = None
        while current is not None:
            if current.data == item:
                if previous is None:
                    self.front = current.next
                else:
                    previous.next = current.next
                    current.next = None
                self.currentSize -= 1
                return True
            previous = current
            current = current.next
            
        return False
    
    def size(self):
        return self.currentSize
    
    def empty(self):
        return self.currentSize == 0
    
    def clear(self):
        self.front = None
        self.back = None
        self.currentSize = 0
        self = LinkedList()
    
    def __str__(self):
        result = ""
        current = self.front
        while current is not None:
            result += "[" + str(current.data) + "]"
            current = current.next
            
        return result
    
    def print_reverse(self):
        print()
        self._print_reverse(self.front)
        print()
        
    def _print_reverse(self, current = None):
        if current is None:
            return
        
        self._print_reverse(current.next)
        print("[" + str(current.data) + "]", end = ' ')

def testLinkedList():
    result = True
    
    mylist = LinkedList()
    
    result &= mylist.size() == 0
    
    mylist.append("bob")
    mylist.append("mob")
    mylist.append("goes")
    
    print(mylist)
    print("size = " + str(mylist.size()))
    result &= mylist.size() == 3
    
    print("contains bob: " + str(mylist.contains("bob")))
    result &= mylist.contains("bob")
    
    mylist.remove("bob")
    result &= not mylist.contains("bob")
    print(mylist)
    print("size = " + str(mylist.size()))
    
    print("contains bob: " + str(mylist.contains("bob")))
    
    mylist.remove("bob")
    result &= not mylist.contains("bob")
    print("size = " + str(mylist.size()))
    result &= mylist.size() == 2
    
    print("contains bob: " + str(mylist.contains("bob")))
    
    print(mylist)
    
    mylist.prepend("end")
    result &= mylist.size() == 3
    mylist.prepend("final end")
    result &= mylist.size() == 4
    print(mylist)
    print("size = " + str(mylist.size()))
    print("contains end: " + str(mylist.contains("end")))
    result &= mylist.contains("end")
    
    print("contains jay: " + str(mylist.contains("jay")))
    result &= not mylist.contains("jay")
    
    mylist.clear()
    result &= mylist.size() == 0
    
    for i in range(100):
        mylist.append('batman-'+str(i))
        result &= mylist.contains('batman-'+str(i))
        
    mylist.print_reverse()
        
    print("Tests passed: " + str(result))

if __name__ == "__main__":
    testLinkedList()


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