TypeError : can only concatenate str(not “int”) to str

   July 16, 2022
TypeError: can only concatenate str(not int) to str

Introduction to TypeError in Python

In this tutorial on TypeError: can only concatenate str(not “int”) to str we are going to learn what is TypeError. Why does this TypeError occur and how we can resolve the issue of the TypeError can only concatenate str(not “int”)to str with examples.

Many new python beginners, come across this kind of TypeError but don’t worry we will resolve it and understand the solution.

Try Short Video Solution

Let’s understand this in detail

What is the TypeError?

The TypeError occurs whenever an operation is performed on an incorrect object or unsupported object type. This issue will appear when you try to concatenate a string with an integer.

Let’s see an example of the addition of two variables

variable1="hello"
variable2= 2
print(variable1+variable2)

In this example, we have added two variables where variable1 is having the value of string type and variable2 is having the value of integer type. But we know the string and the integer cannot be added together. The only solution for this is to concatenate the operands of having the same data type.

Output

Output1 of TypeError: can only concatenate str(not “int”) to str

Let’s see another example of TypeError

String_value = "Welcome"
int_value = 50

print(String_value + int_value)

Output

Output2 of TypeError : can only concatenate str(not "int”) to str

In this example, we can clearly see that the string value and the integer value cannot be concatenated.

What is TypeError: can only concatenate str (not “int”) to str?

Python does not allow concatenating values of different types while other programming language such as javascript supports type coercion which automatically(*) converts values like integers and float so that they can be concatenated. 

In Python, we cannot concatenate a string and an integer, string and a list, etc.

Example Scenario

Let us take a simple example to look at this issue.

products = {
   "product": "Redmi",
   "cost": 1700,
   "stock": 12
}

print("We have total " + products["stock"] + " quantities of Product " + products["product"])

Output

Output3 of TypeError : can only concatenate str(not “int”) to str

Explanation:

In the above example we are getting the error as TypeError: can only concatenate str(not “int”) to str as we are trying to concatenate the string and the integer value together in the print statement.

How to fix TypeError: can only concatenate str(not “int”) to str?

In the Python programming language, before performing the concatenation of the two operands we should make sure that they should be of the same type.

In the above dictionary example, the products[stock] is of type integer and we are concatenating the integer value with strings in the print statement which causes the TypeError: can only concatenate str (not “int”) to str.

We can provide solutions to this problem in different ways

Method1 using str()

The solution to this problem is very simple. As we know that string and integer cannot be concatenated we have to convert the integer value into the string format, before we concatenate and print the result.

Code after we convert the products[stock] into a string

products = {
   "product": "Redmi",
   "cost": 1700,
   "stock": 12
}

print("We are having total " + str(products["stock"])+ " quantities of Product " + products["product"])

Output

Output 4 of TypeError: can only concatenate str(not “int”) to str

As we can see, after converting the product[stock] into string format we are getting the desired result.

Method2 using .fstring {} in the print statement

print(f"We are having total {(products['stock'])} quantities of Product {products['product']}")

Method3 using the %s symbol in the print statement

print("We are having total " '%s' %(products['stock']), " quantities of products " '%s' %(products['product']))

Method4 using the . format in the print statement

print("We are having total " '{}' .format(products['stock']), " quantities of products " '{}' .format(products['product']))

Output

Output5 of TypeError: can only concatenate str(not “int”) to str

In these ways, by using different methods we can convert integer format into string format and display the output without any TypeError.

Summary

The TypeError: can only concatenate str(not “int”) to str usually occurs if we are trying to concatenate an integer with a string. Python does not allow concatenating values of different data types. We can resolve the issue by converting the integer values to strings before concatenating them.

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Author: Ayush Purawr