Difference of using open() vs with open()

Although the function of using open() and with open() is exactly same but, there are some important differences:

• Using open() we can use the file handler as long as the file has not been explicitly closed using file_handler.close(), but in case of using with open() context manager, we cannot use a file handler outside the with block. It will raise ValueError: I/O operation on closed file in that case.
• While using open() we need to explicitly close an opened file instance, else other parts of code may face errors while opening the same file. In with open() the closing of the file is handled by the context manager.
• Using with open() context statement makes the code more tidy as we can easily separate between code block by difference in indents. In case of open(), we might miss closing the file instance, this may cause memory leaks and other I/O operation errors.

The with keyword in Python is used as a context manager. As in any programming language, the usage of resources like file operations or database connections is very common. But these resources are limited in supply. Therefore, the main problem lies in making sure to release these resources after usage. If they are not released, then it will lead to resource leakage and may cause the system to either slow down or crash.

As we know, the open() function is generally used for file handling in Python. But it is a standard practice to use context managers like with keywords to handle files as it will automatically release files once its usage is complete.