Using the type() Function
Concept of the type() Function
The type() function in Python is used to get the type of an object. This function is very useful for data validation, debugging, and writing code that needs to work with different data types.
Syntax:
type(object)
object: The object for which you want to determine the type.
The function returns a type object that represents the type of the given object.
Basic Examples
Checking the Type of a Variable:
x = 10 print(type(x)) # Outputs: <class 'int'> y = "Hello" print(type(y)) # Outputs: <class 'str'>
Checking the Type of a Complex Object:
d = {"name": "Alice", "age": 30}
print(type(d)) # Outputs: <class 'dict'>
Using type() with Dictionaries
When using type() with dictionaries, you can determine the type of both the keys and values. This functionality is useful for debugging and validating data in complex data structures.
Examples:
Type of Keys and Values in a Dictionary:
d = {
"name": "Alice", # Key of type str, value of type str
"age": 30, # Key of type str, value of type int
"scores": [95, 88] # Key of type str, value of type list
}
for key, value in d.items():
print(f"Key: {key}, Type of Key: {type(key)}")
print(f"Value: {value}, Type of Value: {type(value)}")
# Output:
# Key: name, Type of Key: <class 'str'>
# Value: Alice, Type of Value: <class 'str'>
# Key: age, Type of Key: <class 'str'>
# Value: 30, Type of Value: <class 'int'>
# Key: scores, Type of Key: <class 'str'>
# Value: [95, 88], Type of Value: <class 'list'>
Type Comparison
type() can be used to compare the types of objects for conditional checks.
Examples:
Type Checking Before Usage:
def process_value(value):
if type(value) is int:
print("Processing integer")
elif type(value) is str:
print("Processing string")
else:
print("Unknown type")
process_value(10) # Outputs: Processing integer
process_value("test") # Outputs: Processing string
process_value([1, 2]) # Outputs: Unknown type
Type Checking in a Dictionary:
d = {
"age": 25,
"name": "John",
"is_student": True
}
if type(d["age"]) is int:
print("Age is an integer")
if type(d["is_student"]) is bool:
print("is_student is a boolean")
Advanced Usage with type()
- Checking Instance Type: You can use type() to check if an object is an instance of a certain class.
class Person: pass p = Person() print(type(p) is Person) # Outputs: True
- Comparison with isinstance(): The isinstance() function is often preferred for type checks as it supports inheritance and is more flexible than type().
x = 10 print(isinstance(x, int)) # Outputs: True print(isinstance(x, str)) # Outputs: Fals
Summary
- type() Function: Used to obtain the type of an object in Python.
- Usage with Dictionaries: Allows you to determine the type of keys and values in a dictionary.
- Type Comparison: Useful for type checking and conditional logic.
Alternative: isinstance() is often used for more flexible type checking, including support for inheritance.