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Using the Python type() Function

python type

In Python, type refers to the category of a value. It is used to indicate the data type of a variable or an object. The type() function is used to find the type of an object or variable. Python is a dynamically typed language, which means that the type of a variable is determined at runtime.

How to Use Python Type?

Example 1: Using type() function to get the type of a variable

x = 5
y = "Hello World"
z = 3.14
print(type(x))
print(type(y))
print(type(z))

Output:

<class 'int'>
<class 'str'>
<class 'float'>

In this example, we have defined three variables x, y, and z of different data types. We have used the type() function to find the data type of each variable.

Example 2: Using type() function to check the type of an object

class MyClass:
  pass

obj = MyClass()
print(type(obj))

Output:

<class '__main__.MyClass'>

In this example, we have defined a class MyClass and created an object obj of that class. We have used the type() function to find the data type of the object.

Example 3: Using type() function to check if a variable is of a certain type

x = 5
print(type(x) == int)

y = "Hello World"
print(type(y) == str)

z = 3.14
print(type(z) == float)

Output:

True
True
True

In this example, we have used the type() function to check if a variable is of a certain type. We have compared the type of each variable with the desired data type using the == operator.

Example 4: Using isinstance() function to check if an object is an instance of a class

class MyClass:
  pass

obj = MyClass()
print(isinstance(obj, MyClass))

Output:

True

In this example, we have defined a class MyClass and created an object obj of that class. We have used the isinstance() function to check if the object is an instance of the class.

Example 5: Using type() function to create an object of a certain type

x = type('IntList', (list,), {})
print(x)

y = x([1, 2, 3])
print(y)

Output:

<class 'type'>
[1, 2, 3]

In this example, we have used the type() function to create a new class IntList that inherits from the list class. We have then created an object y of the IntList class.

isinstance()

The isinstance() function is used to check if an object is an instance of a class. It takes two arguments: the object and the class. It returns True if the object is an instance of the class, otherwise it returns False.

class MyClass:
  pass

obj = MyClass()
print(isinstance(obj, MyClass))

Output:

True

issubclass()

The issubclass() function is used to check if a class is a subclass of another class. It takes two arguments: the subclass and the superclass. It returns True if the subclass is a subclass of the superclass, otherwise it returns False.

class Animal:
  pass

class Dog(Animal):
  pass

print(issubclass(Dog, Animal))

Output:

True

Type annotations

Type annotations are a way of indicating the data type of a variable or a function argument in Python. They are not enforced by the Python interpreter, but they can be used by external tools for type checking and code analysis.

def add_numbers(x: int, y: int) -> int:
  return x + y

result = add_numbers(5, 10)
print(result)

Output:

15

In this example, we have used type annotations to indicate that the arguments x and y are of type int, and that the return value is of type int.

Conclusion

In conclusion, Python type is an important concept that is used to indicate the data type of a variable or an object. The type function is used to find the type of an object or variable, while the isinstance() function is used to check if an object is an instance of a class. The issubclass() function is used to check if a class is a subclass of another class. Type annotations can be used to indicate the data type of variables and function arguments.

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