A prevalent and omnipresent concept in most programming languages pointers is generally leveraged to create efficiency in programming. They are helpful to speed-up and make repetitive operations more efficient but at the same time can cause a major problem when not done properly, even leading to system crashes. In this post, we will try to understand the concept of pointers, they significance in programming and the concept of pointers specific to Python. The best way to get in-depth theoretical knowledge is to attend a training course from a renowned institution like PST Analytics!
The Concept of Pointers
To understand the concept of pointers and their significance in computer programming, we should first start with how memory management is done. Basically, in any high-level language, a variable is what is used to store data. So, when you create a variable and specify its data-type, the computer interprets that it as needing to create a space in its memory that is sufficient to store the data-type specified. Once executed, space cannot be used for any other purpose. Space becomes available for other programs only when the variable goes “out of scope” and is then is destroyed by the “garbage collectors”.
What is a pointer, and what is its significance?
So, what is a pointer? Basically, a pointer is something that points to the location of the variable stored in the memory. Hence, in simple terms, it is the memory address rather than the value. You can assign values and arrays to a pointer. Basically, the advantage of pointers is that they make the processing fast and light. When you pass values to a function they get stored twice; in case the values are big, it takes up a big chunk of the space. But when you pass a pointer to a function the address of the value is copied. This limits the storage used, making the process more efficient.
Though on the outside, the concept of pointers can seem neat and advantageous, programmers might have to face big problems when not used properly. The basic disadvantage is when the pointers go out of scope, and they are automatically cleared up by garbage collectors. This means you can no longer use the data, but it still lives in the memory. Additionally, attempting to look-up such cleared pointer might cause the system to crash totally. Thus, the attraction of pointers and clear drawbacks are obvious.
What is “Pointers” in Python?
Python is an object-oriented, high-level programming language, popular with a number of programmers around the world, especially due to its incredible speed and high efficiency. So, being a high-level programming language, does Python have pointers? A simple answer to this is Python doesn’t have pointers. Though the reason why they haven’t been provided is unclear experts believe that it might be due to the inherently complex nature of the pointers which is against the principle of simplicity that is embedded in the Python language. Additionally, as stated above, improper use of pointers can cause immense harm, and maybe the removal of the concept is the way to ensure that it doesn’t happen when using Python.
So, whatever the reason, the short answer to the question is Python doesn’t have pointers, but it doesn’t mean that people cannot harness the benefits of the concept of pointers. The concept of pointers can be implemented with the help of other objects in Python.
Understanding memory allocation in Python – Variables vs. Names
To know how to use the concept of pointers in Python it is crucial to understand how memory allocation is done in Python vs other programming languages like C (or C++ which have pointers) since the concept of pointers deals with memory.
Basically, in other programming languages, when you assign a value to a variable after specifying the data-type, it creates a space in the memory with a memory location and variable points to the value. So, if you want to change the value of the variable, later on, the variable points to the same space in the memory, and only the value of the variable is updated.
But when it comes to Python, it doesn’t have variables; it just has names. So, when you want to create a variable in Python and assign a value to it, the first thing that happens is that a PyObject is created with the memory location and value. Next, the variable or the name as it is called is assigned to the PyObject. Thus, if you want to update the value of the variable or the name, rather than just updating the value, a new PyObject is created and assigned the name previously used for the old Pyobject, and the old Pyobject becomes redundant.
The concept of Objects in Python
So, from the above example, it is clear that Python works with objects, and everything in Python is an object. Objects in Python are two types: mutable and immutable objects. The basic difference is that mutable objects can be changed and immutable objects cannot.
Implementing pointers using other objects
Programmers using Python can simulate pointers in two different ways:
- By using mutable types
- And by using custom Python objects
Mutable types as pointers
Since mutable objects can be changed, they can be used to extract the benefits of pointers. So, what are the mutable objects that can be used to mimic pointers? One mutable pointer that can be used to mimic pointers is “list”, and another possible candidate is dict; but one has to keep in mind that they can only be used to mimic pointer behavior and don’t have the characteristics of a pointer.
Using custom objects as pointers
A simpler way to leverage the benefit of pointers is to use custom Python class. For this, you can create a custom class, assess the values using properties, which then become mutable and hence can be used to exhibit pointer behavior.
Thus, it is obvious that Python has more to it than what is apparent at the surface level. In-depth knowledge can help you come up with custom solutions when using this programming language in real-life situations. Good luck!