Statements and Expressions

Statements and Expressions are fundamental units that compose a program.

A statement is a code block that directs the program to perform a specific task.

Statements can take various forms, such as the following:

It stores a value in a variable (a container for data) for reuse later.

To assign a value to a variable, use the = symbol.

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number = 10  # A statement assigning 10 to the variable number

A conditional statement allows the program to execute a specific part of the code based on whether a condition is true or false.

It uses the keywords if, elif (short for "else if"), and else to define different conditions or actions.

Each conditional line must end with a colon (:) to indicate the start of the associated block of code.

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if number > 5:  # If number is greater than 5
    print("The number is greater than 5")  # Statement to print 'The number is greater than 5'

Executes a part of the code multiple times as long as a certain condition is met.

Use the keywords for, while and must append a colon (:) at the end of the line.

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for i in range(3):   # Repeats from 0 to 2
    print(i + 5)     # Statement to print i + 5

• for defines a loop, and i in range(3) denotes the loop range.

• The indented code block under the colon (:) defines what to execute on each loop iteration. The above example adds 5 to i and prints the result for each loop iteration.

• i is the variable used in the loop, taking values 0, 1, and 2 in sequence. Each iteration of the code block increments i by 1.

• The range function generates a series of numbers, and range(3) generates numbers from 0 to 2.

• The loop above runs print(i + 5), outputting 5, 6, and 7 when i is 0, 1, and 2, respectively.

Programs process data, execute code based on conditions, and perform repetitive tasks using various statements.

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a = 1  # Variable assignment statement

for i in range(3):  # Loop statement
    if i == 1:      # Conditional statement
       print(i)     # Print statement

An expression is a unit of code that yields a value.

Expressions are evaluated to produce a single value.

Expressions can be part of a statement and are used as a portion of the task the statement performs.

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# An expression that returns 7
3 + 4 

# An expression that generates the string "Hello World"
"Hello" + " " + "World"

Statements are executed code, while expressions are code that produce a value.

In simple terms, statements tell Python what to do, whereas expressions tell it what to calculate or evaluate.

For example, in the code below, 5 + 3 is an expression, while a = 5 + 3 is a statement that assigns the value 8 to the variable a.

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a = 5 + 3

Complete the conditional statement by typing if number > 5:.

Be careful not to forget the trailing colon(:)! Omitting it results in a syntax error.