Python Statements

A statement is an instruction that a Python interpreter can execute. Learn simple statements and compound statements.

Table of contents

• Python Compound Statements
• Simple Statements
• Expression statements
• The pass statement
• The del statement
• The return statement
• The import statement
• The continue and break statement

1.0 What is a statement in Python

A statement is an instruction that a Python interpreter can execute. So, in simple words, we can say anything written in Python is a statement. Python statement ends with the token NEWLINE character. It means each line in a Python script is a statement.

For example, a = 10 is an assignment statement. where a is a variable name and 10 is its value. There are other kinds of statements such as if statement, for statement, whilestatement, etc.

There are mainly four types of statements in Python,

• print statements,
• Assignment statements, 
• Conditional statements, 
• Looping statements.

The print and assignment statements are commonly used. The result of a print statement is a value. Assignment statements don’t produce a result it just assigns a value to the operand on its left side. A Python script usually contains a sequence of statements. If there is more than one statement, the result appears only one time when all statements execute.

2.0 Compound Statements

Compound statements contain (groups of) other statements; they affect or control the execution of those other statements in some way.

The compound statement includes the conditional and loop statement.

• if statement: It is a control flow statement that will execute statements under it if the condition is true. Also kown as a conditional statement.
• while statements: The while loop statement repeatedly executes a code block while a particular condition is true. Also known as a looping statement.
• for statement: Using for loop statement, we can iterate any sequence or iterable variable. The sequence can be string, list, dictionary, set, or tuple. Also known as a looping statement.
• try statement: specifies exception handlers.
• with statement: Used to cleanup code for a group of statements, while the with statement allows the execution of initialization and finalization code around a block of code.

3.0 Simple Statements

There are various types of simple statement in Python, Python has various simple statements for a specific purpose. Namely

• Expression statements
• The pass statement
• The del statement
• The return statement
• The import statement
• The continue and break statement

1.0 Expression statements

This is a simple statement that assign a value to a variable. But in a script, an expression all by itself doesn’t do anything! So we mostly assign an expression to a variable, which becomes a statement for an interpreter to execute.

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x = 5
# right hand side of = is a expression statement

# y = x + 10 is a complete statement
y = x + 10

2.0 The pass statement

pass is a null operation. Nothing happens when it executes. It is useful as a placeholder when a statement is required syntactically, but no code needs to be executed.

For example, you created a function for future releases, so you don’t want to write a code now. In such cases, we can use a pass statement.

Example:

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# create a function
def fun1(arg):
    pass  # a function that does nothing (yet)

3.0 The del statement

The Python del statement is used to delete objects/variables.

Syntax:

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del target_list

The target_list contains the variable to delete separated by a comma. Once the variable is deleted, we can’t access it.

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x = 10
y = 30
print(x, y)

# delete x and y
del x, y

# try to access it
print(x, y)

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10 30
NameError: name 'x' is not defined

4.0 The return statement

We create a function in Python to perform a specific task. The function can return a value that is nothing but an output of function execution.

Using a return statement, we can return a value from a function when called.

Example:

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# Define a function
# function accepts two numbers and return their sum

def addition(num1, num2):
    return num1 + num2  # return the sum of two numbers

# result is the return value
result = addition(10, 20)
print(result)


# Output
30

5.0 The import statement

The import statement is used to import modules. We can also import individual classes from a module. Python has a huge list of built-in modules which we can use in our code. For example, we can use the built-in module DateTime to work with date and time.

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import datetime

# get current datetime
now = datetime.datetime.now()
print(now)

# Output
2021-08-30 18:30:33.103945

6.0 The continue and break statement

• break Statement: The break statement is used inside the loop to exit out of the loop.
• continue Statement: The continue statement skip the current iteration and move to the next iteration.