How do I concatenate strings with a space or a new line?

Add the space inside one of the strings, like "Hello, " + name, or use join() with the separator you need: " ".join(items) for spaces and "\n".join(items) for one item per line.

Why do I get the error can only concatenate str (not "int") to str?

Because you are joining text and a number with +. Python does not convert types on its own: use str(number) or an f-string.

What is the most efficient way to concatenate many strings in Python?

Store the pieces in a list and join them at the end with join(). Repeating += thousands of times inside a loop is less clear and can be slower.

How do I join the items of a list into one string in Python?

Use join() with the separator first: " ".join(words) or ", ".join(words). If the list has numbers, convert them first with ", ".join(map(str, items)).

What is an f-string in Python?

It is a string with an f before the quotes where you can put variables and expressions inside curly braces, like f"Total: {price * 2}". It exists since Python 3.6 and is the most readable way to build text.

How do I concatenate a number and a string in Python?

Convert it with str(): "You are " + str(age) + " years old". Or use an f-string, which converts it for you: f"You are {age} years old".

How do I concatenate strings in Python?

Use the + operator to join a few strings, like "Hello, " + name. If you mix text with variables or numbers, use an f-string: f"{name} is {age} years old". To join a list, use " ".join(items).

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How to concatenate Strings on Python

Join text, variables, numbers and lists with +, f-strings and join(), and avoid the usual concatenation errors.

6 min readLast updated Nov 9, 2026

How do you concatenate strings in Python?

Short answer: use the + operator to join two or three strings, an f-string when you mix text with variables or numbers, and join() when you have a list of strings:

python

name = "Ana"
age = 30
 
print("Hello, " + name)                 # Hello, Ana
print(f"{name} is {age} years old")     # Ana is 30 years old
print(" ".join(["Learn", "Python"]))    # Learn Python

+ only joins text: to add a number, convert it with str() or use an f-string.

The + operator only joins text. f-strings convert numbers for you, and join() combines a whole list with the separator you choose.

Ways to concatenate strings in Python

Method	Example	Use it to
`+`	`"Hello, " + name`	Join a few strings
`+=`	`text += "!"`	Add text to a variable
f-string	`f"{name} is {age} years old"`	Mix text, variables and numbers
`join()`	`" ".join(words)`	Join a list with a separator
`format()`	`"{} is {} years old".format(name, age)`	Older code or reusable templates
`%`	`"%s is %d years old" % (name, age)`	Read very old code
`*`	`"-" * 20`	Repeat a string

Concatenate with the + operator

python

name = "Alex"
 
print("My name is " + name + " and I'm a developer")
# My name is Alex and I'm a developer

+ does not add spaces. If you forget the space after is, you get My name isAlex.

Add text with +=

python

greeting = "Hello"
greeting += ", world"
 
print(greeting)  # Hello, world

Python strings cannot be changed: += creates a new string and stores it in the same variable.

Concatenate with f-strings

Put an f before the quotes and write the variables inside curly braces. You can also do math and formatting inside the braces:

python

product = "Keyboard"
price = 20
 
print(f"{product}: ${price * 1.08:.2f} with tax")
# Keyboard: $21.60 with tax

f-strings convert numbers to text for you and are the most readable option in modern Python.

Join a list with join()

python

words = ["Learn", "to", "code"]
 
print(" ".join(words))   # Learn to code
print("-".join(words))   # Learn-to-code
print("\n".join(words))  # one word per line

The string before .join() is the separator. join() only accepts text: if the list has numbers, convert them first with map(str, items):

python

print(", ".join(map(str, [1, 2, 3])))  # 1, 2, 3

To learn more, see how to convert a list to a string in Python.

Concatenate numbers and text

python

age = 30
 
print("You are " + str(age) + " years old")  # You are 30 years old
print(f"You are {age} years old")            # You are 30 years old

Without str(), "You are " + age raises TypeError: can only concatenate str (not "int") to str.

format(), % and *

python

name = "Ana"
age = 30
 
print("{} is {} years old".format(name, age))  # Ana is 30 years old
print("%s is %d years old" % (name, age))      # Ana is 30 years old
print("ha" * 3)                                # hahaha

format() and % still work, but in new code an f-string reads better. * repeats a string as many times as you ask.

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Concatenate many strings in a loop

If you are joining many pieces, store them in a list and join them at the end with join(). It is clearer and more efficient than repeating += thousands of times:

python

parts = []
for i in range(3):
    parts.append(f"line {i}")
 
print("\n".join(parts))
# line 0
# line 1
# line 2

Join long strings across several lines

Two string literals written next to each other inside parentheses are joined automatically, without +:

python

message = ("Learn to code "
           "with Python")
 
print(message)  # Learn to code with Python

Use string concatenation with AI

When you code with AI, you concatenate strings all the time: the prompts you send to a model are built with f-strings and join():

python

text = "Python is a programming language widely used in AI."
n = 1
 
prompt = f"Summarize this text in {n} sentence: {text}"
print(prompt)
# Summarize this text in 1 sentence: Python is a programming language widely used in AI.

An assistant like ChatGPT, Claude or GitHub Copilot also helps you write and fix that code. These three prompts are ready to copy.

1. Pick the best way

I have these variables in Python: [paste your variables and their values]
I want to get this text: [write the result you expect]
Write it with an f-string and, if there is a list, with join(). Explain why.

2. Fix a concatenation error

When I concatenate strings in Python I get this error: [paste the full error]
This is my code: [paste your code]
Explain the cause and give me the fix.

3. Build a prompt for an AI model

Help me write a Python function that takes [a text and a number of sentences]
and returns a prompt for an AI model using f-strings. Show me an example call.

Always check the answer by running it in your terminal or in Jupyter.

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Common errors when concatenating strings

What you see	Why it happens	Fix
`TypeError: can only concatenate str (not "int") to str`	You are joining text and a number with `+`	Use `str(number)` or an f-string
`TypeError: unsupported operand type(s) for +: 'int' and 'str'`	The number comes first in the sum	Same: `str(number)` or an f-string
`TypeError: sequence item 1: expected str instance, int found`	The list passed to `join()` has numbers	Use `", ".join(map(str, items))`
`AttributeError: 'list' object has no attribute 'join'`	You wrote `items.join(" ")`	The separator goes first: `" ".join(items)`
`{name}` is printed literally	You forgot the `f` before the quotes	Write `f"{name}"`
Words come out stuck together, like `HelloAna`	`+` does not add spaces	Add the space inside the string or use `" ".join(...)`

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Frequently asked questions about concatenating strings in Python

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How to concatenate Strings on Python

How do you concatenate strings in Python?

Ways to concatenate strings in Python

Concatenate with the + operator

Add text with +=

Concatenate with f-strings

Join a list with join()

Concatenate numbers and text

format(), % and *

You can join strings, now build prompts and AI apps

Concatenate many strings in a loop

Join long strings across several lines

Use string concatenation with AI

From joining text to AI applications

Common errors when concatenating strings

Related guides

Concatenating strings in a 2-page cheat sheet

Frequently asked questions about concatenating strings in Python

How do I concatenate strings with a space or a new line?

Why do I get the error can only concatenate str (not "int") to str?

What is the most efficient way to concatenate many strings in Python?

How do I join the items of a list into one string in Python?

What is an f-string in Python?

How do I concatenate a number and a string in Python?

How do I concatenate strings in Python?