🧵 Python String Formatting — Writing Clean & Dynamic Text Output

Introduction 🌟

String formatting allows you to insert variables, values, and expressions inside strings dynamically. It makes your output clean, readable, and professional — essential for building real-world applications.

Note

💡 Python offers multiple formatting methods: f-strings, format(), and % formatting. The recommended and modern way is **f-strings**.

1. Why String Formatting? 🤔

Without formatting, combining strings and variables becomes messy:

without_formatting.py

name = "Sathish"
age = 25
print("My name is " + name + " and I am " + str(age) + " years old.")

This is hard to read. Let's fix it with formatting! 🚀

2. f-Strings (Best & Recommended) ✨

Introduced in Python 3.6, f-strings allow embedding variables using .

fstring_basic.py

name = "Sathish"
age = 25
print(f"My name is {name} and I am {age} years old.")

Use expressions inside f-strings

fstring_expressions.py

print(f"Next year, you will be {age + 1}")

Formatting numbers

fstring_numbers.py

price = 49.5678
print(f"Price: {price:.2f}")  # 2 decimal places

Alignment with f-strings

fstring_alignment.py

print(f"{'Python':>10}")  # right aligned
print(f"{'Python':<10}")  # left aligned
print(f"{'Python':^10}")  # center aligned

Note

⚡ f-Strings are the fastest and cleanest string formatting method.

3. format() Method 🧰

The format() function allows placeholder-based formatting using .

Basic Usage

format_basic.py

name = "Sathish"
age = 25
print("My name is {} and I am {} years old.".format(name, age))

Positional Arguments

format_positional.py

print("I live in {1} and my name is {0}".format("Sathish", "India"))

Named Arguments

format_named.py

print("Name: {name}, Age: {age}".format(name="Sathish", age=25))

Formatting Numbers

format_numbers.py

print("Value: {:.2f}".format(3.14159))

4. % Formatting (Older Style) 📜

This is the oldest Python formatting method, still seen in legacy code.

percent_format.py

name = "Sathish"
age = 25
print("My name is %s and I am %d years old." % (name, age))
  • %s → String
  • %d → Integer
  • %f → Float

5. Formatting Dictionaries 🗂️

dict_format.py

person = {"name": "Sathish", "age": 25}
print("Name: {name}, Age: {age}".format(**person))

6. Formatting with Padding & Alignment 🎯

padding_alignment.py

print("{:>10}".format("Python"))  # right align
print("{:<10}".format("Python"))  # left align
print("{:^10}".format("Python"))  # center align

7. Formatting Numbers (Advanced) 🔢

Thousands Separator

thousands.py

num = 1234567
print(f"{num:,}")  # 1,234,567

Percentage Formatting

percentage.py

value = 0.85
print(f"Success rate: {value:.2%}")

Scientific Notation

scientific.py

print(f"{1234:e}")

8. Combining Strings With Variables 🧩

combine.py

product = "Laptop"
price = 59999
print(f"The {product} costs Rs.{price:,}")

9. Real-World Example 🌍

real_world_example.py

name = input("Enter your name: ")
score = float(input("Enter your score: "))

print(f"Hello {name}, your score is {score:.2f}!")

Conclusion 🎉

>>"String formatting makes your output elegant, readable, and professional — a must-know skill for every Python developer." ✨

You have now mastered all key string formatting techniques in Python! Want to continue with Operators, Expressions, Conditional Statements, Loops, Functions, Lists, Tuples, or Dictionaries? Just tell me your next topic! 😊