Page 399 - Computer_Science_F5

Computer Science consisting of four spaces, to define code Variables
blocks within functions, loops, and
(a) Variable declaration
conditional statements. By adhering
Python does not require a specific
to consistent indentation practices, the
command for declaring a variable. In
structure and hierarchy of the code
FOR ONLINE READING ONLY
become clear and easily understandable.
when you assign a value to it for the
For example, Python, a variable is automatically created
first time. There is no need to explicitly
if x > 100: declare the variable beforehand. Once
print(“x is greater than 100”) a value is assigned to a variable, it is
else: stored in memory and can be referenced
print(“x is not greater than 100”) by its assigned name throughout the
program. This dynamic nature of variable
In this example, the two prints has creation simplifies the coding process
gone inside to the right by four space and allows for more flexibility in Python
leaving if and else at the left. If you skip programming. For example,
indentation, Python will give you an x = 256
error message, For example: y = “Mwanamweru”

if x > 100: print(x)
print(“x is greater than 100”) print(y)
else:
print(“x is not greater than 100”) (b) Variable naming
In Python, variables can have both
This program will give you an error. It short and descriptive names. However,
is important to use the same number of there are certain rules and guidelines to
spaces in the same block of code so that follow. These include:
Python will not give you an error (i) A variable name must begin with a
letter or an underscore character.
(b) Comments (ii) It cannot start with a number.
In Python, comments are denoted by the #
symbol and serve the purpose of explaining (iii) It can only consist of alphanumeric
code or adding notes. Comments are not characters (letters and numbers) and
interpreted by the Python interpreter and underscores.
are solely meant for human readers. They (iv) Variable names are case-sensitive,
provide additional context, improve code meaning that variables with different
readability, and can serve as reminders or capitalization are considered distinct
explanations for future reference. (such as age, Age, and AGE are
For example, treated as separate variables).
(v) Python keywords cannot be used
#This is a comment for this code
as variable names, as they have

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for Advanced Secondary Schools

Computer Science Form 5.indd 390 23/07/2024 12:34