With

Programs often use resources other than CPU time, including access to local disks, network sockets, and databases etc. The usage pattern is usually a try-except-finally block. Any cleanup actions are performed in the finally block. An alternative to the usual boilterplate code is to use the with statement. The with statement wraps the execution of a block of statements in a context defined by a context manager object.

Context Management Protocol

A context manager object abides by the context management protocol, which states that an object defines the following two methods. Python calls these two methods at appropriate times in the resource management cycle:

• __enter__()

• __exit__()

The with statement is used as:

    with context-expression [as target]:
        statement#1
        statement#2
            .
            .
            .
        statement#n