Python syntax, data types, and variables

Python Syntax:

Python is known for its clean and readable syntax. Here are some fundamental syntax rules:

  1. Statements and Indentation:
    • Python uses indentation (whitespace) to define blocks of code, rather than curly braces {}. This is a unique feature of Python and helps in maintaining a clean and consistent code structure.

    Example:

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    if condition:
    # This block is indented, it belongs to the if statement
    print("This is indented")
else:
    print("This is also indented")
  2. Comments:
    • Comments start with a # character and are ignored by the Python interpreter. They are used to add explanations or notes within the code.

    Example:

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    # This is a comment
  3. Variables and Identifiers:
    • Variables are used to store data. In Python, you can assign a value to a variable using =. Identifiers are names given to variables, functions, classes, etc.

    Example:

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    # Variable assignment
x = 10
name = "John"

# Identifiers
my_variable = 5
  4. Data Types:
    • Python has several built-in data types, including integers, floats, strings, booleans, lists, tuples, dictionaries, etc. We’ll discuss them in more detail below.

Data Types:

1. Numeric Types:

  • int: Integer numbers (e.g., -5, 0, 100)
  • float: Floating-point numbers (e.g., 3.14, -0.5)

Examples:

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   num_int = 42
   num_float = 3.14

2. String:

  • A sequence of characters enclosed in single (‘ ‘), double (“ “), or triple (‘’’ ‘’’ or “”” “””) quotes.

Examples:

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   name = "Alice"
   message = 'Hello, world!'

3. Boolean:

  • Represents truth values True or False.

Examples:

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   is_valid = True
   has_permission = False

4. List:

  • Ordered collection of items, which can be of different types.

Example:

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   my_list = [1, 2, 3, "hello", True]

5. Tuple:

  • Similar to lists but immutable (cannot be changed after creation).

Example:

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   my_tuple = (1, 2, 3, "world")

6. Dictionary:

  • Collection of key-value pairs.

Example:

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

7. Set:

  • Unordered collection of unique items.

Example:

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   my_set = {1, 2, 3, 4, 4, 4}  # Only contains 1, 2, 3, 4

Examples:

Let’s combine these concepts in some examples:

Example 1: Variables and Basic Operations

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# Variables and basic operations
x = 5
y = 3

# Arithmetic operations
sum_result = x + y
difference_result = x - y
product_result = x * y
division_result = x / y

print(sum_result, difference_result, product_result, division_result)

Lists:

Example 1 - Creating and Manipulating Lists:

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# Creating a list
my_list = [1, 2, 3, 4, 5]

# Accessing elements
print("First element:", my_list[0])
print("Last element:", my_list[-1])

# Modifying elements
my_list[2] = 10
print("Modified list:", my_list)

# Appending and removing elements
my_list.append(6)
my_list.remove(4)
print("Updated list:", my_list)

Tuples:

Example 2 - Creating and Accessing Tuples:

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# Creating a tuple
my_tuple = (1, 2, 3, 4, 5)

# Accessing elements
print("First element:", my_tuple[0])
print("Last element:", my_tuple[-1])

Dictionaries:

Example 3 - Creating and Manipulating Dictionaries:

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# Creating a dictionary
my_dict = {'name': 'John', 'age': 30, 'city': 'New York'}

# Accessing values
print("Name:", my_dict['name'])
print("Age:", my_dict['age'])

# Adding a new key-value pair
my_dict['email'] = 'john@example.com'
print("Updated dictionary:", my_dict)

# Iterating through keys and values
for key, value in my_dict.items():
    print(f"{key}: {value}")

Sets:

Example 4 - Creating and Operating on Sets:

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# Creating a set
my_set = {1, 2, 3, 4, 4, 4}

# Adding and removing elements
my_set.add(5)
my_set.remove(2)
print("Updated set:", my_set)

Sample Program for all data types

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# Integer
integer_var = 42
print("Integer Variable:", integer_var)

# Float
float_var = 3.14
print("Float Variable:", float_var)

# String
string_var = "Hello, World!"
print("String Variable:", string_var)

# List
list_var = [1, 2, 3, 4, 5]
print("List Variable:", list_var)

# Tuple
tuple_var = (10, 20, 30, 40, 50)
print("Tuple Variable:", tuple_var)

# Dictionary
dict_var = {'a': 1, 'b': 2, 'c': 3}
print("Dictionary Variable:", dict_var)

# Set
set_var = {1, 2, 3, 4, 5}
print("Set Variable:", set_var)

# Basic tasks

# Integer and Float operations
result = integer_var + float_var
print("Integer + Float:", result)

# String concatenation
new_string = string_var + " Have a nice day!"
print("Concatenated String:", new_string)

# List manipulation
list_var.append(6)
list_var.remove(2)
print("Modified List:", list_var)



# Dictionary operations
dict_var['d'] = 4
del dict_var['a']
print("Modified Dictionary:", dict_var)

# Set operations
set_var.add(6)
set_var.remove(3)
print("Modified Set:", set_var)