11/09/2013

How Python keeps variables in a separate list from values? Lesson-3

For the purpose of this course, you may think of computer memory as a long list of storage locations where each location is identified with a unique number and each location houses a value. This unique number is called a memory address. Typically, we will write memory addresses as a number with an "id" as a prefix to distinguish them from other numbers (for example, id201 is memory address 201).
Variables are a way to keep track of values stored in computer memory. A variable is a named location in computer memory. Python keeps variables in a separate list from values. A variable will contain a memory address, and that memory address contains the value. The variable then refers to the value. Python will pick the memory addresses for you.

Some Terminology which are used in Python 

A value has a memory address.
A variable contains a memory address.
A variable refers to a value.
A variable points to a value.


Example: Value 8.5 has memory address id34.
Variable shoe_size contains memory address id34.
The value of shoe_size is 8.5.
shoe_size refers to value 8.5.
shoe_size points to value 8.5.
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