Introduction to Data Types and Control Flow in Python

Python Data Types

Understanding data types is fundamental to programming in Python. Data types define the kind of data that can be stored and manipulated within a program.

 

Numeric Types

Python supports three distinct numeric types:

 

Integers (int): Whole numbers without a decimal point.

Floating-Point Numbers (float): Numbers with a decimal point.

Complex Numbers (complex): Numbers with a real and an imaginary part.

 

Code:

# Integer

x = 10

 

# Floating-Point

y = 3.14

 

# Complex

z = 1 + 2j

 

print(type(x))  # <class 'int'>

print(type(y))  # <class 'float'>

print(type(z))  # <class 'complex'>

 

String Type

Strings in Python are sequences of characters enclosed in single quotes ('), double quotes ("), or triple quotes (''' or """).

 

Code:

# Single quotes

str1 = 'Hello, World!'

 

# Double quotes

str2 = "Python is fun!"

 

# Triple quotes (for multi-line strings)

str3 = '''This is a

multi-line

string.'''

 

print(str1)

print(str2)

print(str3)

List Type

A list is an ordered collection of items, which can be of different types. Lists are mutable, meaning their elements can be changed.

 

Code:

my_list = [1, 2, 3, "apple", "banana"]

print(my_list)

 

# Accessing elements

print(my_list[0])  # 1

print(my_list[3])  # apple

 

# Modifying elements

my_list[1] = "orange"

print(my_list)

 

Tuple Type

A tuple is similar to a list, but it is immutable, meaning once created, its elements cannot be changed.

 

Code:

my_tuple = (1, 2, 3, "apple", "banana")

print(my_tuple)

 

# Accessing elements

print(my_tuple[0])  # 1

print(my_tuple[3])  # apple

 

# Trying to modify an element (will raise an error)

# my_tuple[1] = "orange"

 

Dictionary Type

A dictionary is an unordered collection of key-value pairs. Each key is unique and immutable, while the values can be of any type and can be modified.

 

Code:

my_dict = {"name": "John", "age": 30, "city": "New York"}

print(my_dict)

 

# Accessing elements

print(my_dict["name"])  # John

print(my_dict["age"])   # 30

 

# Modifying elements

my_dict["age"] = 31

print(my_dict)

 

Set Type

A set is an unordered collection of unique elements. Sets are mutable, but their elements must be immutable.

 

Code:

my_set = {1, 2, 3, 3, 4, 5}

print(my_set)  # {1, 2, 3, 4, 5}

 

# Adding elements

my_set.add(6)

print(my_set)

 

# Removing elements

my_set.remove(2)

print(my_set)

 

Control Flow

Control flow statements allow you to execute specific blocks of code based on certain conditions or repeatedly execute a block of code.

 

Conditional Statements

Conditional statements (if, elif, else) execute different blocks of code based on conditions.

 

Code:

x = 10

 

if x > 0:

    print("x is positive")

elif x < 0:

    print("x is negative")

else:

print("x is zero")

 

Loops

Loops allow you to execute a block of code repeatedly.

 

for Loop

The for loop iterates over a sequence (such as a list, tuple, or string) or other iterable objects.

 

Code:

# Iterating over a list

fruits = ["apple", "banana", "cherry"]

for fruit in fruits:

    print(fruit)

 

# Iterating over a range of numbers

for i in range(5):

print(i)

 

while Loop

The while loop executes as long as a condition is true.

 

Code:

count = 0

while count < 5:

    print(count)

count += 1

 

Break and Continue Statements

The break statement exits the loop, while the continue statement skips the rest of the code inside the loop for the current iteration and jumps to the next iteration.

 

Code:

# Using break

for i in range(10):

    if i == 5:

        break

    print(i)

 

# Using continue

for i in range(10):

    if i % 2 == 0:

        continue

print(i)