Unsupported operand type s for int and str ошибка

This type of error would be caused by something along these lines:

"some string" + anInt - anotherInt

The problem arises because of the String in this statement- the compiler interprets the plus sign as combining the String and int together. However, in this context, it doesn’t know what to do with a minus sign- you can’t subtract an int from a string.

Your problem can be solved by putting your integer operations inside sets of parenthesis- i.e.,

"some string" + (anInt - anotherInt)

If you’re still having trouble, we can review your exact code and see where these parenthesis should be added- but this may be enough to get by on your own, which is always preferable!

EDIT: I’ll leave the above post in case it is part of the issue as well, but after reviewing the code again, you have this line of code:

A = ( (14 - 'month') /12)

In which you’re subtracting the String ‘month’ from the int 14. That’d probably be a problem.

Python provides support for arithmetic operations between numerical values with arithmetic operators. Suppose we try to perform certain operations between a string and an integer value, for example, concatenation +. In that case, we will raise the error: “TypeError: unsupported operand type(s) for +: ‘str’ and ‘int’”.

This tutorial will go through the error with example scenarios to learn how to solve it.

TypeError: unsupported operand type(s) for +: ‘int’ and ‘str’

What is a TypeError?

TypeError tells us that we are trying to perform an illegal operation for a specific Python data type. TypeError exceptions may occur while performing operations between two incompatible data types. In this article, the incompatible data types are string and integer.

Artithmetic Operators

We can use arithmetic operators for mathematical operations. There are seven arithmetic operators in Python:

All of the operators are suitable for integer operands. We can use the multiplication operator with string and integer combined. For example, we can duplicate a string by multiplying a string by an integer. Let’s look at an example of multiplying a word by four.

string = "research"

integer = 4

print(string * integer)

researchresearchresearchresearch

Python supports multiplication between a string and an integer. However, if you try to multiply a string by a float you will raise the error: TypeError: can’t multiply sequence by non-int of type ‘float’.

However, suppose we try to use other operators between a string and an integer. Operand x is a string, and operand y is an integer. In that case, we will raise the error: TypeError: unsupported operand type(s) for: [operator]: ‘str’ and ‘int’, where [operator] is the arithmetic operator used to raise the error. If operand x is an integer and operand y is a string, we will raise the error: TypeError: unsupported operand type(s) for: [operator]: ‘int’ and ‘str’. Let’s look at an example scenario.

Example: Using input() Without Converting to Integer Using int()

Python developers encounter a common scenario when the code takes an integer value using the input() function but forget to convert it to integer datatype. Let’s write a program that calculates how many apples are in stock after a farmer drops off some at a market. The program defines the current number of apples; then, the user inputs the number of apples to drop off. We will then sum up the current number with the farmer’s apples to get the total apples and print the result to the console. Let’s look at the code:

num_apples = 100

farmer_apples = input("How many apples are you dropping off today?: ")

total_apples = num_apples + farmer_apples

print(f'total number of apples: {total_apples}')

Let’s run the code to see what happens:

How many apples are you dropping off today?: 50

---------------------------------------------------------------------------
TypeError                                 Traceback (most recent call last)
1 total_apples = num_apples + farmer_apples

TypeError: unsupported operand type(s) for +: 'int' and 'str'

We raise the because Python does not support the addition operator between string and integer data types.

Solution

The solve this problem, we need to convert the value assigned to the farmer_apples variable to an integer. We can do this using the Python int() function. Let’s look at the revised code:

num_apples = 100

farmer_apples = int(input("How many apples are you dropping off today?: "))

total_apples = num_apples + farmer_apples

print(f'total number of apples: {total_apples}')

Let’s run the code to get the correct result:

How many apples are you dropping off today?: 50

total number of apples: 150

Variations of TypeError: unsupported operand type(s) for: ‘int’ and ‘str’

If we are trying to perform mathematical operations between operands and one of the operands is a string, we need to convert the string to an integer. This solution is necessary for the operators: addition, subtraction, division, modulo, exponentiation and floor division, but not multiplication. Let’s look at the variations of the TypeError for the different operators.

TypeError: unsupported operand type(s) for -: ‘int’ and ‘str’

The subtraction operator – subtracts two operands, x and y. Let’s look at an example with an integer and a string:

x = 100

y = "10"

print(f'x - y = {x - y}')

---------------------------------------------------------------------------
TypeError                                 Traceback (most recent call last)
1 print(f'x - y = {x - y}')

TypeError: unsupported operand type(s) for -: 'int' and 'str'

Solution

We must convert the y variable to an integer using the int() function to solve this. Let’s look at the revised code and result:

x = 100

y = "10"

print(f'x - y = {x - int(y)}')

x - y = 90

TypeError: unsupported operand type(s) for /: ‘int’ and ‘str’

The division operator divides the first operand by the second and returns the value as a float. Let’s look at an example with an integer and a string :

x = 100

y = "10"

print(f'x / y = {x / y}')

---------------------------------------------------------------------------
TypeError                                 Traceback (most recent call last)
1 print(f'x / y = {x / y}')

TypeError: unsupported operand type(s) for /: 'int' and 'str'

Solution

We must convert the y variable to an integer using the int() function to solve this. Let’s look at the revised code and result:

x = 100

y = "10"

print(f'x / y = {x / int(y)}')

x / y = 10.0

TypeError: unsupported operand type(s) for %: ‘int’ and ‘str’

The modulus operator returns the remainder when we divide the first operand by the second. If the modulus is zero, then the second operand is a factor of the first operand. Let’s look at an example with an and a string.

x = 100

y = "10"

print(f'x % y = {x % y}')

---------------------------------------------------------------------------
TypeError                                 Traceback (most recent call last)
1 print(f'x % y = {x % y}')

TypeError: unsupported operand type(s) for %: 'int' and 'str'

Solution

We must convert the y variable to an integer using the int() function to solve this. Let’s look at the revised code and result:

x = 100

y = "10"

print(f'x % y = {x % int(y)}')

x % y = 0

TypeError: unsupported operand type(s) for ** or pow(): ‘int’ and ‘str’

The exponentiation operator raises the first operand to the power of the second operand. We can use this operator to calculate a number’s square root and to square a number. Let’s look at an example with an integer and a string:

x = 100

y = "10"

print(f'x ** y = {x ** y}')

---------------------------------------------------------------------------
TypeError                                 Traceback (most recent call last)
1 print(f'x ** y = {x ** y}')

TypeError: unsupported operand type(s) for ** or pow(): 'int' and 'str'

Solution

We must convert the y variable to an integer using the int() function to solve this. Let’s look at the revised code and result:

x = 100

y = "10"

print(f'x ** y = {x ** int(y)}')

x ** y = 100000000000000000000

TypeError: unsupported operand type(s) for //: ‘int’ and ‘str’

The floor division operator divides the first operand by the second and rounds down the result to the nearest integer. Let’s look at an example with an integer and a string:

x = 100

y = "10"

print(f'x // y = {x // y}')

---------------------------------------------------------------------------
TypeError                                 Traceback (most recent call last)
1 print(f'x // y = {x // y}')

TypeError: unsupported operand type(s) for //: 'int' and 'str'

Solution

We must convert the y variable to an integer using the int() function to solve this. Let’s look at the revised code and result:

x = 100

y = "10"

print(f'x // y = {x // int(y)}')

x // y = 10

Summary

Congratulations on reading to the end of this tutorial! The error: TypeError: unsupported operand type(s) for +: ‘int’ and ‘str’ occurs when we try to perform addition between an integer value and a string value. Python does not support arithmetic operations between strings and integers, excluding multiplication. To solve this error, ensure you use only integers for mathematical operations by converting string variables with the int() function. If you want to concatenate an integer to a string separate from mathematical operations, you can convert the integer to a string. There are other ways to concatenate an integer to a string, which you can learn in the article: “Python TypeError: can only concatenate str (not “int”) to str Solution“. Now you are ready to use the arithmetic operators in Python like a pro!

Go to the online courses page on Python to learn more about coding in Python for data science and machine learning.

Have fun and happy researching!

Ситуация: начинающий программист более-менее освоил JavaScript и перешёл к Python. Чтобы освоить новый язык на практике, программист решил переписать свой старый проект с JavaScript на Python и столкнулся с таким фрагментом:

var a = 2;
var b = ' ствола';
var c = a + b;

Программист помнит, что в Python для переменных не нужен var, а можно просто объявлять их в нужном месте, поэтому он написал такой код:

a = 2
b = ‘ ствола’
c = a + b

Но при запуске проекта компьютер указал на последнюю строку и выдал ошибку:

Exception has occurred: TypeError
unsupported operand type(s) for +: ‘int’ and ‘str’

Почему так происходит: в JavaScript есть автоматическое приведение типов, и компьютер берёт на себя перевод данных из одного типа в другой. В нашем примере он сделает так:

Но Python так не умеет — ему нужно, чтобы данные были одного типа или хотя бы из одного семейства: оба числовые, оба строковые и так далее. Так как сейчас идёт сложение разных типов данных, то Питон говорит, что он так делать не будет, и падает с ошибкой.

Что делать с ошибкой Exception has occurred: TypeError

Чтобы исправить эту ошибку, нужно вручную привести данные к одному типу или явно указать их при операции.

В нашем случае можно сделать так: при сложении сказать компьютеру напрямую, что мы хотим в сложении использовать переменную a как строку:

a = 2
b = ‘ ствола’
c = str(a) + b

Команда str() не меняет тип и содержимое переменной a, но зато компьютер понимает, что это временно стало строкой, и спокойно её складывает со второй строкой.

Как исправить: TypeError: неподдерживаемые типы операндов для -: 'str' и 'int'

Integer values cannot be subtracted from string values and vice versa. This is because strings and integers are separate data types. If you try to subtract a string from an integer, you receive an error like “TypeError: unsupported operand type(s) for -: ‘str’ and ‘int’”.

In this guide, we talk about the significance of this error and why it is raised. We walk through an example to help you figure out how to solve this error in your code.

TypeError: unsupported operand type(s) for -: ‘str’ and ‘int’

Unlike other programming languages, Python syntax is strongly typed. One consequence of this is you have to change the types of objects, like strings and integers, if you want to treat them as a different type of data.

When you try to subtract a string for an integer or vice versa, Python does not know what to do. This is because you cannot subtract string values.

Similarly, you cannot add a string to an integer or divide a string by an integer. These operations all return an “unsupported operand type(s)” error.

An Example Scenario

We’re going to build a spending application that tracks how much money someone will have left on their budget after making a purchase. This application asks a user to insert the value of each purchase they make. This will be subtracted from the total amount a user has in their budget.

To start, ask a user to set a budget using the input() method:

budget = int(input("What is your budget for this month? "))

We have converted this value to an integer using the int() method. Next, we ask a user to provide some details about their purchase. We ask about what they purchased and how much their purchase cost:

purchase = input("What did you purchase? ")
price = input("How much was this purchase? ")

Next, we subtract the value of “price” from “budget”. This tells us how much a user has left in their budget.

We do this using the subtraction operator (-):

money_left = budget - price
print("You have ${} left in your budget.".format(money_left))

Run our code to see if our program works:

What is your budget for this month? 400
What did you purchase? Monitor stand
How much was this purchase? 35

Traceback (most recent call last):
  File "main.py", line 5, in <module>
	money_left = budget - price
TypeError: unsupported operand type(s) for -: 'int' and 'str'

We’ve told our program our budget is $400 for the month. We have just purchased a monitor stand that cost $35. Our program fails to calculate our new budget. Let’s fix this error.

The Solution

To solve this error, we convert the value of “price” to a string.

By default, input() returns a string. We changed the value of “budget” to be an integer earlier in our code. However, we did not change the value of “price”. This results in our code subtracting an integer from a string which is not possible.

Python cannot automatically convert a string to an integer because Python is statically typed.

We solve this error by replacing the “price” declaration with this code:

price = int(input("How much was this purchase? "))

We have surrounded the input() statement with int(). This makes the value stored in the “price” variable an integer. This converts the value a user inserts into our program to an integer. Run our code with this revised line of code:

What is your budget for this month? 400
What did you purchase? Monitor stand
How much was this purchase? 35
You have $365 left in your budget.

Our code runs successfully. Our code subtracts 35 from 400. Our program then prints out how much money we have left in our budget to the console.

Similar Errors

There are a number of “unsupported operand type(s)” errors in Python.

These errors mean the same thing: you are trying to perform a mathematical operation on a string and a numerical value. Because strings do not support mathematical operations, you’ll encounter an error.

For instance, you see this error if you try to add a string and an integer:

TypeError: unsupported operand type(s) for +: 'int' and 'str'

Similarly, you see this error if you try to find the remainder of a string and an integer:

TypeError: unsupported operand type(s) for %: 'int' and 'str'

To solve this error in all cases, make sure you convert any string values to an integer before you use them in your code. You can do this using the int() method.

Conclusion

The “TypeError: unsupported operand type(s) for -: ‘str’ and ‘int’” error is raised when you try to subtract a string from an integer.

You solve this error by converting all strings to integers using the int() method before performing a mathematical operation.

Now you’re ready to solve this common Python error like a professional developer!