(This Gist can be accessed at http://goo.gl/ZYAZkC.)
In Python we use variable to refer to objects. In other words, a variable is a name for an object.
This Gist is an explanation of how Python creates variable names, and how it decides what object a variable name refers to.
| """ | |
| The aliasing demo code. | |
| This is meant to be entered into a Python shell, bit-by-bit. (That's | |
| why some lines appear to do nothing-- they will produce the | |
| representation of the object when evaluated in the REPL.) | |
| """ | |
| import person |
| kernel: file format elf32-i386 | |
| Disassembly of section .text: | |
| 80100000 <multiboot_header>: | |
| 80100000: 02 b0 ad 1b 00 00 add 0x1bad(%eax),%dh | |
| 80100006: 00 00 add %al,(%eax) | |
| 80100008: fe 4f 52 decb 0x52(%edi) |
I'll explain the relationship between objects and names. That is, I'll explain aliasing.
In Python, we create objects and give them names. It's important to understand objects, names, and their relationship to each other-- at the very least it will help you avoid some bugs!
We create objects to represent data. For example, when we execute a = [4, 25], Python sees the [4, 25] and creates a list object.
When we create an object, we want to be able to refer back to it later. So we make a name that points to it. Above, we made the name a and pointed it at a list object. Then, when we use that name in a statement, Python finds the object that it points to so we can do things with the object-- like printing its value or modifying its data. For example, to execute a.append(400), Python looks at the name a, finds the object that it points to (the list), and then modifies the list by appending the value 400 to it.
We're allowed to have multiple names point to a single object. For example, we c