Python Scripting For Linux System Administrators — Variables

Variable is a name that is used to refer to memory location. Python variable is also known as an identifier and used to hold value.

We can assign a value to a variable by using a single = and we don’t need to (nor can we) specify the type of the variable.

>>> my_str = "This is a simple string"

Now we can print the value of that string by using my_var later on:

>>> print(my_str)
This is a simple string

We can’t change a string because it’s immutable. This is easier to see now that we have variables.

>>> my_str += " testing"
>>> my_str
'This is a simple string testing'

That didn’t change the string; it reassigned the variable. The original string of "This is a simple string" was unchanged.

An important thing to realize is that the contents of a variable can be changed and we don’t need to maintain the same type:

>>> my_str = 1
>>> print(my_str)
1

Ideally, we wouldn’t change the contents of a variable called my_str to be an int, but it is something that python would let use do.

One last thing to remember is that if we assign a variable with another variable, it will be assigned to the result of the variable and not whatever that variable points to later.

>>> my_str = 1
>>> my_int = my_str
>>> my_str = "testing"
>>> print(my_int)
1
>>> print(my_str)
testing

Finally Some Rules:

a) A variable name must start with a letter or the underscore character.
b) A variable name cannot start with a number.
c) A variable name can only contain alpha-numeric characters and underscores (A-z, 0–9, and _ ).
d) Variable names are case-sensitive (name, Name and NAME are three different variables).
e) The reserved words(keywords) cannot be used naming the variable.

That’s all!

Hope you like the article. Please let me know your feedback in the response section.

To access my earlier articles on Python Strings go here, Python Numbers go here.

Thanks. Happy learning!