Python String Concatenation: How to Combine Strings and Variables

Whether you're displaying a welcome message, generating a dynamic filename, or building a chatbot response — string concatenation is something you'll use often in Python.

In this post, you’ll learn all the practical ways to concatenate strings and variables in Python, including tips and gotchas.

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✅ 1. Using the + Operator

The + operator is the simplest and most intuitive way to concatenate strings.

💡 Example:

name = "Raj" greeting = "Hello " + name + ", welcome!" print(greeting)

🧠 Output:

Hello Raj, welcome!

⚠️ Important:

If you try to concatenate a string with a number, you'll get an error:

age = 30 print("You are " + age + " years old.")  # ❌ TypeError!

To fix it, convert the number to a string:

print("You are " + str(age) + " years old.")  # ✅

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✅ 2. Using f-Strings (Formatted String Literals) — 🏆 Best Practice

f-Strings (introduced in Python 3.6) are the most modern, readable, and flexible way to combine strings and variables.

💡 Example:

name = "Raj" age = 48 message = f"Hello {name}, you are {age} years old." print(message)

🧠 Output:

Hello Raj, you are 48 years old.

👍 Benefits:

• No need to convert variables to string manually
  
  

• Cleaner syntax
  
  

• Supports expressions like f"{2 + 3}" or f"{name.upper()}"
  
  

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✅ 3. Using the format() Method

The format() method is an older but still useful approach, especially for Python versions earlier than 3.6.

💡 Example:

name = "Raj" age = 30 message = "Hello {}, you are {} years old.".format(name, age) print(message)

🧠 Output:

Hello Raj, you are 30 years old.

You can also use named placeholders:

message = "Hello {name}, age {age}.".format(name="Raj", age=30)

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✅ 4. Using the % Operator (Old Style — Not Recommended)

This was common in Python 2 but is mostly replaced by f-strings and format() in modern code.

💡 Example:

name = "Raj" age = 30 message = "Hello %s, you are %d years old." % (name, age)

While still supported, it’s more error-prone and less readable than modern methods.

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🎯 Real-World Example: Building a Sentence

Here’s how all these methods look side by side:

name = "Raj" city = "Madurai" age = 35 # Method 1: + print("Name: " + name + ", City: " + city + ", Age: " + str(age)) # Method 2: f-string print(f"Name: {name}, City: {city}, Age: {age}") # Method 3: format() print("Name: {}, City: {}, Age: {}".format(name, city, age))

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🧼 Best Practices

• Use f-strings whenever possible. They are the cleanest and easiest.
  
  

• Avoid using + with numbers unless you explicitly convert them to str.
  
  

• Only use format() if you need backward compatibility with Python < 3.6.
  
  

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🧵 Summary Table

Method	Example	Use Case
+ Operator	"Hello " + name	Simple, strings only
f-String	f"Hello {name}, age {age}"	✅ Recommended for all Python 3.6+
format()	"Hello {}, age {}".format(name, age)	Backward compatible
% Operator	"Hello %s" % name	Old codebases only

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🧑‍💻 Final Thoughts

String concatenation is a basic skill, but choosing the right method improves readability, performance, and safety of your code. Now that you know how to combine strings and variables the Pythonic way — go ahead and build your next chatbot, logger, or welcome screen!