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Python Cheat Sheet (DRAFT) by

Generalized Python Code

This is a draft cheat sheet. It is a work in progress and is not finished yet.

__init__

class my_class:
    def __init__(self, field_one, field_two):
        self.field_one = field_one
        self.field_two = field_two

my_instance = my_class(42, "hello")  # __init__ is called here
The constr­uctor method called automa­tically when a new instance of a class is created.
Receives the arguments passed to the class and uses them to set up the instance's fields.
Without it you cannot pass any values when creating an instance.

!r

my_value = "some text"

f"{my_value}"    # some text
f"{my_value!r}"  # 'some text'
Adds repr() formatting to a value inside an f-string, wrapping strings in quotes and showing escape characters explic­itly.
Useful for debugging and error messages where you want to see the exact value including its type hints.
Without !r a string is inserted as plain text; with !r it is wrapped in quotes so it's unambi­guous.
  

__repr__

class my_class:
    def __repr__(self):
        return f"my_class(field_one={self.field_one}, field_two={self.field_two})"

my_instance = my_class(42, "hello")
print(my_instance)  # my_class(field_one=42, field_two=hello)
Defines how an object is repres­ented as a string when printed or inspected.
Should return a string that clearly describes the object and its contents.
Used by print(), debuggers, and the intera­ctive console.
  

__eq__

class my_class:
    def __eq__(self, other):
        return self.field_one == other.field_one and self.field_two == other.field_two

instance_a = my_class(42, "hello")
instance_b = my_class(42, "hello")
instance_a == instance_b  # True — same field values
instance_a is instance_b  # False — different objects in memory
Defines what equality means for two instances of a class.
Without it, == checks if two variables point to the same object in memory rather than comparing their contents.
Should return True if all relevant fields are equal, False otherwise.