Introduction to Python functions: functions and examples of the id function

Introduction to Python functions: functions and examples of the id function

The id() function in Python is a built-in function that can return the memory address of an object. This memory address is an integer that uniquely identifies the location of the object in the computer's memory. The syntax of the id() function is as follows:

id(object)

Among them, object is the object that needs to obtain the memory address, which can be any object in Python such as numbers, strings, lists, tuples, dictionaries, sets, etc.

The return value of the id() function is an integer, representing the address of the object in computer memory. If the return values ​​of id() of two objects are equal, then they are the same object.

The following are some examples to help you better understand the function of the id() function:

# 示例1：获取整数对象的内存地址
a = 123
print(id(a))    # 输出：140707313355888

# 示例2：获取字符串对象的内存地址
b = 'hello'
print(id(b))    # 输出：4350869408

# 示例3：获取列表对象的内存地址
c = [1, 2, 3]
print(id(c))    # 输出：4350088200

# 示例4：判断两个对象是否相等
d = [1, 2, 3]
e = [1, 2, 3]
print(id(d) == id(e))       # 输出：False
print(id(d) == id(d))       # 输出：True

As can be seen from the examples, the return values ​​​​of id() for the same object are equal, The return values ​​of id() for different objects are not equal. Additionally, even if two objects have the same value, their id() return values ​​may not be equal because they are stored in different locations in computer memory.

In actual programming, the id() function is often used to compare whether two objects are equal. If the return values ​​of the id() functions of two objects are equal, then they can be considered to be the same object and can be compared directly using the "==" operator. However, it should be noted that the id() function can only be used to compare whether mutable objects are equal. The "==" operator should be used to compare whether immutable objects are equal.

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