The print() Function
The print() Function Syntax in Python ๐จ๏ธ
The basic syntax of the print() function in Python is:
Python
print(*objects, sep=' ', end='\n', file=sys.stdout, flush=False)
Let’s break down each part:
print(): This is the function name.*objects(positional argument, arbitrary number):- This represents one or more items (objects) that you want to print.
- You can pass numbers, strings, variables, lists, dictionaries, results of expressions, etc.
- If you pass multiple objects, they will be converted to strings and printed.
sep=' '(keyword argument, optional):- This stands for “separator”.
- It specifies how the
objectsare separated when multiple items are printed. - By default, it’s a single space character (
' '). - You can change it to any string, e.g.,
sep=','for comma-separated values, orsep='---'for dashes.
end='\n'(keyword argument, optional):- This specifies what to print at the end of the output.
- By default, it’s a newline character (
'\n'), which means afterprint()finishes, the cursor moves to the next line. - You can change it to an empty string (
end='') to keep the cursor on the same line, or any other string.
file=sys.stdout(keyword argument, optional):- This specifies where the output should go.
- By default, it’s
sys.stdout, which means the output is sent to the standard output device (usually your console or terminal). - You can redirect the output to a file by providing a file object, e.g.,
file=my_file_object.
flush=False(keyword argument, optional):- This is a boolean argument that controls whether the output stream is forcibly flushed.
- When
True, the output is immediately written to thefile. - When
False(default), the output might be buffered, meaning it’s held in memory for a short time before being written, which can be more efficient for large outputs.
Simple Examples to Illustrate: ๐ก
Python
# 1. Printing a single string
print("Hello, Python!") # Output: Hello, Python!
# 2. Printing multiple objects with default separator
name = "Alice"
age = 30
print("Name:", name, "Age:", age) # Output: Name: Alice Age: 30
# 3. Changing the separator
print("Apple", "Banana", "Cherry", sep="-") # Output: Apple-Banana-Cherry
# 4. Preventing a newline at the end
print("Loading...", end="")
print("Done!") # Output: Loading...Done!
# 5. Redirecting output to a file
# with open("log.txt", "w") as f:
# print("This message goes to a file!", file=f)
# # This will write "This message goes to a file!" into a new file named log.txt
# 6. Printing expressions
print(2 + 3 * 4) # Output: 14
Basic print() Function in Python with Examples ๐จ๏ธ
The print() function is used to display output in Python. It can print text, numbers, variables, or any combination of these.
1. Simple Print Statement ๐ฃ๏ธ
Prints a string or number directly:
Python
print("Hello, World!") # Output: Hello, World!
print(42) # Output: 42
2. Printing Multiple Items ๐งฉ
Separates items with a space by default:
Python
name = "Alice"
age = 25
print("Name:", name, "Age:", age) # Output: Name: Alice Age: 25
3. Changing the Separator (sep) โ๏ธ
Use sep to customize how items are separated:
Python
print("Python", "Java", "C++", sep=" | ") # Output: Python | Java | C++
4. Preventing Line Breaks (end) โก๏ธ
Override the default newline (\n) with end:
Python
print("Hello", end=" ")
print("World!") # Output: Hello World!
5. Printing Special Characters โจ
Use escape sequences for formatting:
Python
print("Line1\nLine2\tIndented")
# Output:
# Line1
# Line2 Indented
6. Printing Variables with f-strings (Python 3.6+) ๐ฌ
Embed variables directly in strings:
Python
name = "Bob"
print(f"Hello, {name}!") # Output: Hello, Bob!
Key Takeaways ๐ฏ
- Basic Syntax:
print("text")orprint(variable). ๐ - Multiple Items: Separate with commas (default space separator). โ
- Custom Separators: Use
sep="|"to change the delimiter. โ๏ธ - No Newline: Set
end=""to print on the same line. โก๏ธ - f-strings: Clean way to embed variables (Python 3.6+). โจ
The print() function is essential for debugging and displaying results in Python! ๐
Here are 10 practical examples of f-strings in Python, covering basic to advanced usage: โจ
1. Basic Variable Insertion ๐
Embed variables directly in strings.
Python
name = "Alice"
age = 25
print(f"My name is {name} and I'm {age} years old.")
# Output: My name is Alice and I'm 25 years old.
2. Mathematical Expressions โ
Perform calculations inside the f-string.
Python
x = 10
y = 3
print(f"{x} + {y} = {x + y}")
# Output: 10 + 3 = 13
3. Number Formatting ๐ข
Control the display of numbers.
A. Round Floats ๐ข. Specify the number of decimal places.
Python
pi = 3.14159
print(f"Pi โ {pi:.2f}") # 2 decimal places
# Output: Pi โ 3.14
B. Add Commas to Large Numbers ๐ฒ Improve readability of large numbers.
Python
population = 1_000_000
print(f"Population: {population:,}")
# Output: Population: 1,000,000
C. Percentages ๐ Format as a percentage.
Python
ratio = 0.75
print(f"Completion: {ratio:.0%}")
# Output: Completion: 75%
4. String Alignment โ๏ธ
Align text within a specified width.
Python
text = "Python"
print(f"{text:>10}") # Right-aligned (10 spaces)
print(f"{text:<10}") # Left-aligned
print(f"{text:^10}") # Centered
# Output:
# Python
# Python
# Python
5. Date Formatting ๐
Format datetime objects.
Python
from datetime import datetime
today = datetime.now()
print(f"Today: {today:%B %d, %Y}")
# Output: Today: June 23, 2025 (or current date)
6. Dictionary Values ๐
Access dictionary values directly.
Python
user = {"name": "Bob", "age": 30}
print(f"{user['name']} is {user['age']} years old.")
# Output: Bob is 30 years old.
7. Function Calls ๐
Embed function calls within the string.
Python
def greet(name):
return f"Hello, {name}!"
print(f"{greet('Alice')}")
# Output: Hello, Alice!
8. Debugging (Python 3.8+) ๐
Print variable name and value for quick debugging.
Python
x = 42
print(f"{x = }") # Prints variable name and value
# Output: x = 42
9. Multiline F-Strings ๐
Create formatted multiline strings.
Python
name = "Alice"
score = 95.5
print(f"""
Name: {name}
Score: {score:.1f}/100
""")
# Output:
# Name: Alice
# Score: 95.5/100
10. Conditional Logic ๐ค
Use a ternary operator for simple conditions.
Python
age = 17
print(f"{'Adult' if age >= 18 else 'Minor'}")
# Output: Minor
Key Advantages of F-Strings โจ
- Readability: Embed variables/expressions directly in strings. ๐
- Performance: Faster than
%formatting or.format(). ๐ - Flexibility: Supports expressions, formatting, and even debugging. ๐คธ
When to Use F-Strings? ๐ก
- Dynamic messages (e.g., user greetings). ๐ฌ
- Formatting numbers/dates. ๐ข๐
- Debugging complex variables. ๐
F-strings make your code cleaner and more efficient! โ