Declaration and Reassignment
We'll cover the following
Declaring single variables
In Python, a variable is created during assignment. Python is type inferred — therefore there is no need to explicitly define a variable’s type. It can simply be created by naming it and then assigning any value irrespective of the type to it.
Example
For instance, let’s name a variable moving_average
. To save or assign a value to it, we will use the assignment operator (=) followed by the said value.
moving_average = 10.2name_of_language = "Python"main_languages = ['Python', 'JavaScript', 'C++', 'Java', 'GO']
Here, the variables are moving_average
, name_of_language
, and main_languages
, and each variable has a different type of value. 10.2, “Python”, and [‘Python’, ‘JavaScript’, ‘C++’, ‘Java’, ‘GO’] are literals. In Python, literals refer to a specific and fixed value of a variable at any instant.
Literals, in Python, refer to a specific and fixed value at any instant.
Note: We can not use reserved keywords to name variables. The following table shows the list of reserved keywords found in Python 3.12.0.
False | assert | continue | except | if | nonlocal | return |
None | async | def | finally | import | not | try |
True | await | del | for | in | or | while |
and | break | elif | from | is | pass | with |
as | class | else | global | lambda | raise | yield |
Reassigning Variables
When there is a need to update a variable, they can be reassigned values easily as well
Example
Suppose the moving_average
changes to 10.5, Python allows changing the value of a variable by simply reassigning it again.
moving_average = 10.5print(moving_average)
Declaring Multiple Variables
We can define multiple variables in one line by following a comma separated syntax. Python also provides for the ease of saving the same value in more than one variable.
Example
For example, let’s create two variables, called mean
and median
, and save 5 and 7 in them, respectively. Let’s also create sorted_list
and sorted_list2
and save [‘1’, ‘2’, ‘3’, ‘4’] in both of these variables.
mean, median = 5, 7print(mean, median)sorted_list = sorted_list2 = ['1', '2', '3', '4']print(sorted_list)print(sorted_list2)