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print(“x is negative”)
Computer Science Data types (b) Looping Constructs: for and while
Python supports several built-in data
else:
types including numeric types( such as
print(“x is zero”)
int, float, complex), sequence types (such
as string, lists, turples and dictionary),
FOR ONLINE READING ONLY
Boolean type (such as bool) and other
type (Such as null ) Python offers two primary looping
constructs: the “for” loop and the “while”
loop. The “for” loop is utilised to iterate
Control flow and decision making in over a sequence, which can be a list,
Python tuple, string, or any other iterable object.
(a) Conditional Statements: if, elif, else It allows you to perform a specific set
In Python, conditional statements are of actions for each item in the sequence
used to execute different blocks of code or execute a fixed number of iterations.
based on specific conditions. The syntax This loop is particularly useful when
for the “if” statement is as follows: you know the number of iterations in
advance or when you want to process
if condition: each element in a given sequence. For
# Block of code to execute if condition example,
is True
animals = [‘lion’, ‘leopard’, ‘buffalo’]
The “elif” statement, short for “else if,” for animal in animals:
enables you to evaluate multiple conditions
consecutively. It allows you to check for print(animal)
additional conditions if the conditions in
the preceding “if” statement(s) are not The “while” loop is employed to
met. execute a block of code repeatedly as
long as a specified condition remains
On the other hand, the “else” statement is true. It allows you to create a loop that
used to execute a block of code when the continues until the condition evaluates
conditions of the “if” or “elif” statements to false. This type of loop is useful
are evaluated as False. It provides an when the number of iterations is not
alternative code path to be executed when known in advance, and the loop should
the previous conditions are not satisfied. continue until a certain condition is met
Here is an example that demonstrates the or becomes false. For example,
usage of these statements:
count = 0
x = 10 while count < 7:

if x > 0:
print(“x is positive”) print(count)
elif x < 0: count += 1

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for Advanced Secondary Schools

Computer Science Form 5.indd 392 23/07/2024 12:34