How do I display the object data of this list pulled from random number generator?

Question

I'm a newbie and have hit a brick wall when trying to call back and display the data of this list. Instead I get only object IDs.

<__main__.Square object at 0x000001FBDF9C7040>
<__main__.Circle object at 0x000001FBDF9C6F80>
<__main__.Cuboid object at 0x000001FBDF9C6E90>

class Cuboid:
    def __init__(self, length=4.0, width=3.0, height=2.0):`
        self.length = length
        self.width = width
        self.height = height
    def setLength(self, length):
        self.length = length
    def setWidth(self, width):
        self.width = width
    def setHeight(self,height):
        self.height = height
    def calArea(self):
        return (2 * self.length * self.width) + (2 * self.length * self.height) + (2 * self.height * self.width)
    def display(self):
        print("With length", self.length, "width", self.width, "and height", self.height)
        print("the area of the cuboid is", self.calArea())
        print("\n")

class Circle:
    def __init__(self, radius=4.3):
        self.radius = radius
    def setRadius(self, radius):
        self.radius = radius
    def calArea(self):
        return self.radius * 2 * math.pi
    def display(self):
        print("With a radius of " + str(self.radius))
        print("the area is ", self.calArea())
        print("\n")

class Square:
    def __init__(self, length=4.0):
        self.length = length
    def setLength(self, length):
        self.length = length
    def calArea(self):
        return self.length * self.length
    def display(self):
        print("With length of sides being " + str(self.length))
        print("the area of the square is", self.calArea())
        print("\n")

def randomizer():
    x = 10
    while x > 0:
        pick = random.randint(0,2)
        print(pick, "was randomly selected.")
        if pick == 0:
            circleObj = Circle()
            ranlist.append(circleObj)
            circleObj.display()
        if pick == 1:
            squareObj = Square()
            ranlist.append(squareObj)
            squareObj.display()
        if pick == 2:    
            cuboidObj = Cuboid()
            ranlist.append(cuboidObj)
            cuboidObj.display()
        x -= 1

def main():
    randomizer()
    for x in range(0, len(ranlist)):
        print (str(ranlist[x]))

main()

Googling has led me to try declaring str() and using __str__ and __repr__ but I feel like I just keep breaking it, assuming I am either implementing it incorrectly, or perhaps the problem is with my class structure to begin with. I can print display() just fine on its own, but when printing from the list gives only object IDs.

What would you like the output to look like? For each of these classes, implement a `def __str__(self):` that does that. There is also a `__repr__` method for human visible display. str is pretty, repr is technical (usually including a hint on what the object type is). When printing a list, python will use each value's `__repr__`. If you want its prettier form, you would `print(", ".join(val) for val in lst)`. — tdelaney, Dec 09 '22 at 23:18

score 0 · Answer 1 · answered Dec 09 '22 at 23:19

Understanding you want to print properties of an object for every object in your list, you can get all the properties of a given object as a dictionary with vars(your_object) and prettyprint it.

See Is there a built-in function to print all the current properties and values of an object? for reference. To prevent deadlink, top answer was:

from pprint import pprint
pprint(vars(your_object))

score 0 · Answer 2 · answered Dec 09 '22 at 23:22

Replace:

print (str(ranlist[x]))

with:

ranlist[x].display()

Or define __str__() methods in your classes that return the same strings that the display() methods currently print. E.g.

class Square:
    def __init__(self, length=4.0):
        self.length = length

    def setLength(self, length):
        self.length = length

    def calArea(self):
        return self.length * self.length

    def __str__(self):
        return f"""With length of sides being {self.length)}
the area of the square is {self.calArea()}"""

    def display(self):
        print(str(self))

Andreas · Accepted Answer · 2022-12-10T00:01:27.000

You can define a base class doing the describing job and let objects derive functionality from:

from numpy import random
import math


class DisplayableBase:
    def __str__(self):
        return self.describe()
    def describe(self):
        return "(undefined)"
    def display(self):
        print(str(self))
    
class Cuboid(DisplayableBase):
    def __init__(self, length=4.0, width=3.0, height=2.0):
        self.length = length
        self.width = width
        self.height = height
    def setLength(self, length):
        self.length = length
    def setWidth(self, width):
        self.width = width
    def setHeight(self, height):
        self.height = height
    def calArea(self):
        return ((self.length * self.width) + 
                (self.length * self.height) + 
                (self.height * self.width)) * 2
    def describe(self):
        return (f"With length {self.length}, "
                f"width {self.width}, and height {self.height}\n"
                f"the area of the cuboid is {self.calArea()}\n")

class Circle(Displayable):
    def __init__(self, radius=4.3):
        self.radius = radius
    def setRadius(self, radius):
        self.radius = radius
    def calArea(self):
        return self.radius**2 * math.pi
    def describe(self):
        return f"With a radius of {self.radius}, the area is {self.calArea()}\n"

class Square(Displayable):
    def __init__(self, length=4.0):
        self.length = length
    def setLength(self, length):
        self.length = length
    def calArea(self):
        return self.length * self.length
    def describe(self):
        return (f"With length of sides being {self.length}, the "
               f"area of the square is {self.calArea()}\n")

def randomizer():
    x = 10
    ranlist = []
    while x > 0:
        pick = random.randint(3)
        print(pick, "was randomly selected.")
        if pick == 0:
            obj = Circle()
        elif pick == 1:
            obj = Square()
        elif pick == 2:    
            obj = Cuboid()
        ranlist.append(obj)
        obj.display()
        x -= 1
    return ranlist

def main():
    ranlist = randomizer()
    for x in ranlist:
        print(str(x))
        #print(x.describe())
        #x.display()

main()

(I corrected some other errors, too)

How do I display the object data of this list pulled from random number generator?

3 Answers3