Syntax:
Python code is typically written in a text editor or integrated development environment (IDE) and saved as a file with a .py extension. The basic syntax of Python is designed to be easy to read and understand, with indentation used to denote code blocks instead of braces or other symbols.
Here’s an example of a simple Python script:
# This is a comment # This is a variable assignment name = "Alice" # This is a print statement print("Hello, " + name + "!")
This code assigns a string value to a variable called “name” and uses the print function to display a message that includes the value of the variable.
Data Types:
Python supports several built-in data types, including integers, floating-point numbers, strings, booleans, and lists. Here are some examples and sample code for each data type:
1. Integers:
Integers are whole numbers without decimal points, such as 1, 2, 3, etc.
# This is an integer assignment age = 25 # This is an integer calculation years_left = 65 - age # This is a print statement with integer values print("You have " + str(years_left) + " years until retirement.")
2. Floating-Point Numbers:
Floating-point numbers are numbers with decimal points, such as 1.0, 2.5, 3.14159, etc.
# This is a floating-point assignment pi = 3.14159 # This is a floating-point calculation circumference = 2 * pi * 5 # This is a print statement with floating-point values print("The circumference of a circle with radius 5 is " + str(circumference) + ".")
3. Strings:
Strings are sequences of characters, such as “hello”, “world”, “Python”, etc.
# This is a string assignment greeting = "Hello, World!" # This is a string concatenation message = greeting + " My name is " + name + "." # This is a print statement with string values print(message)
4. Booleans:
Booleans are values that represent either true or false, such as True or False.
# This is a boolean assignment is_student = True # This is a boolean condition if is_student: print("You qualify for a student discount!") else: print("Sorry, you do not qualify for a student discount.")
5. Lists:
Lists are ordered collections of values, such as [1, 2, 3], [“apple”, “banana”, “cherry”], etc.
# This is a list assignment fruits = ["apple", "banana", "cherry"] # This is a list indexing second_fruit = fruits[1] # This is a list append fruits.append("orange") # This is a print statement with list values print("My favorite fruits are: " + ", ".join(fruits) + ".")
These are just a few examples of the basic syntax and data types in Python. There are many more data types and advanced features available in Python, such as dictionaries, tuples, sets, functions, and classes, which can be used to write more complex and powerful programs.
6. Dictionaries:
Dictionaries are collections of key-value pairs, such as {“name”: “Alice”, “age”: 25, “city”: “New York”}.
# This is a dictionary assignment person = {"name": "Alice", "age": 25, "city": "New York"} # This is a dictionary lookup person_age = person["age"] # This is a dictionary update person["city"] = "Los Angeles" # This is a print statement with dictionary values print(person)
7. Tuples:
Tuples are similar to lists, but they are immutable (cannot be changed after creation), such as (1, 2, 3), (“apple”, “banana”, “cherry”), etc.
# This is a tuple assignment coordinates = (3, 4) # This is a tuple unpacking x, y = coordinates # This is a print statement with tuple values print("The coordinates are (" + str(x) + ", " + str(y) + ").")
8. Sets:
Sets are unordered collections of unique values, such as {1, 2, 3}, {“apple”, “banana”, “cherry”}, etc.
# This is a set assignment numbers = {1, 2, 3, 4, 5} # This is a set intersection even_numbers = {2, 4, 6, 8, 10} common_numbers = numbers.intersection(even_numbers) # This is a print statement with set values print("The common even numbers are: " + ", ".join(str(num) for num in common_numbers) + ".")
These examples demonstrate how Python supports a variety of data types and features that can be used to solve a wide range of programming problems. As you continue to learn Python, you’ll discover many more advanced data types and features that can help you write more efficient, powerful, and elegant code.
9. Strings:
Strings are collections of characters, such as “hello”, “world”, “Python”, etc.
# This is a string assignment message = "Hello, world!" # This is a string concatenation name = "Alice" greeting = "Hello, " + name + "!" # This is a string interpolation age = 25 message = "My name is {0} and I am {1} years old.".format(name, age) # This is a print statement with string values print(message)
10. Lists:
Lists are ordered collections of values, such as [1, 2, 3], [“apple”, “banana”, “cherry”], etc.
# This is a list assignment numbers = [1, 2, 3, 4, 5] # This is a list slicing first_three_numbers = numbers[:3] last_two_numbers = numbers[-2:] # This is a list comprehension squared_numbers = [num ** 2 for num in numbers] # This is a print statement with list values print("The squared numbers are: " + ", ".join(str(num) for num in squared_numbers) + ".")
11. Booleans:
Booleans are True or False values, which can be used to control program flow and logic, such as True, False, 1 == 1, 2 > 3, etc.
# This is a boolean assignment is_raining = True # This is a boolean comparison is_sunny = False is_nice_weather = is_sunny or not is_raining # This is a boolean expression temperature = 25 is_hot_weather = temperature >= 30 and is_sunny # This is a print statement with boolean values print("It is nice weather: " + str(is_nice_weather) + ", and it is hot weather: " + str(is_hot_weather) + ".")
These examples demonstrate how Python supports a variety of data types and features that can be used to solve a wide range of programming problems. As you continue to learn Python, you’ll discover many more advanced data types and features that can help you write more efficient, powerful, and elegant code.