Using dir() to find variables and functions

After assigning values to a few variables, we could use the dir() function to show their existence. In the following example, variables n, pv, and r are shown among other names. At the moment, just ignore the first five objects in the following code, which start and end with two underscores:

>>>pv=100
>>>r=0.1
>>>n=5
>>>dir()
['__builtins__', '__doc__', '__loader__', '__name__', '__package__', 'n', 'pv', 'r']

Deleting or unsigning a variable

Sometimes, when we write our programs, it might be a good idea to delete those variables that we no longer need. In this case, we could use the del() function to remove or unsign a variable. In the following example, we assign a value to rate, show its value, delete it, and type the variable name trying to retrieve its value again:

>>>rate=0.075
>>>rate
0.075

The value 0.075 seen...