PythonInput and OutputOutput

Output in Python

In Python, the most common way to display output is by using the built-in print() function. It writes data to the standard output (typically the console or terminal).

Python also supports advanced output formatting with:

  • String concatenation
  • Formatted string literals (f-strings)
  • str.format() method

Basic Usage of print()

print_basic.py
print("Hello, World!")
output.txt
Hello, World!

Explanation:

  • print() takes one or more arguments and displays them, separated by a space, followed by a newline.

Example 1: Printing Multiple Items

print_multiple.py
print("Python", "is", "fun!")
output.txt
Python is fun!

Explanation:

  • print() separates multiple arguments with spaces by default.

Example 2: Printing Variables

print_variables.py
name = "Alice"
age = 30
print(name, "is", age, "years old.")
output.txt
Alice is 30 years old.

Controlling Separators and End

Using sep argument

print_sep.py
print("Python", "Java", "C++", sep=", ")
output.txt
Python, Java, C++

Using end argument

print_end.py
print("Hello,", end=" ")
print("World!")
output.txt
Hello, World!

Explanation:

  • sep changes the separator between arguments.
  • end changes what is printed after the final argument (default is newline \n).

Example 3: String Concatenation with +

print_concat.py
first = "Hello"
second = "World"
print(first + ", " + second + "!")
output.txt
Hello, World!

Explanation:

  • You can concatenate strings using +.
  • You must manually handle spaces and punctuation.

Example 4: Using f-strings (Formatted String Literals)

print_fstring.py
name = "Bob"
score = 95.5
print(f"Student {name} scored {score} marks.")
output.txt
Student Bob scored 95.5 marks.

Explanation:

  • Introduced in Python 3.6.
  • An f before the string allows embedding expressions inside {}.

Example 5: Using str.format()

print_format.py
product = "Laptop"
price = 899.99
print("The {} costs ${:.2f}".format(product, price))
output.txt
The Laptop costs $899.99

Explanation:

  • str.format() inserts values into placeholders {}.
  • :.2f formats the float to 2 decimal places.

Example 6: Formatting Numbers

print_numbers.py
num = 1234567.891
print(f"Formatted number: {num:,.2f}")
print(f"Binary: {42:b}")
print(f"Hexadecimal: {255:x}")
output.txt
Formatted number: 1,234,567.89
Binary: 101010
Hexadecimal: ff

Explanation:

  • :, adds comma as thousands separator.
  • b prints binary, x prints hexadecimal.

Example 7: Printing Collections

print_collections.py
fruits = ["apple", "banana", "cherry"]
print(f"Fruits: {fruits}")
 
person = {"name": "Alice", "age": 28}
print(f"Person: {person}")
output.txt
Fruits: ['apple', 'banana', 'cherry']
Person: {'name': 'Alice', 'age': 28}

Summary

  • The print() function is versatile and easy to use.

  • You can customize output using:

    • sep and end
    • String concatenation with +
    • f-strings (recommended)
    • str.format()

  • Python makes it simple to display formatted data of any type.

InputType Casting