EOFError: EOF when reading a line
I am trying to define a function to make the perimeter of a rectangle. Here is the code:
I think I haven’t left any arguments opened or anything like that.
3 Answers 3
Running it like this produces:
I suspect IDLE is simply passing a single string to your script. The first input() is slurping the entire string. Notice what happens if you put some print statements in after the calls to input() :
Running echo «1 2» | test.py produces
Notice the first print statement prints the entire string ‘1 2’ . The second call to input() raises the EOFError (end-of-file error).
So a simple pipe such as the one I used only allows you to pass one string. Thus you can only call input() once. You must then process this string, split it on whitespace, and convert the string fragments to ints yourself. That is what
How to fix EOFError: EOF when reading a line
When using the input() or raw_input() function in Python, you might see the following error:
This error usually occurs when the input() function reached the end-of-file (E0F) without reading any input.
There are two scenarios where this error might occur:
- When you interrupt the code execution with CTRL + D while an input() function is running
- You called the input() function inside a while loop
- You’re using an Online Python IDE and you don’t provide any input in STDIN
This tutorial will show how to fix this error in each scenario.
1. Interrupting code execution with CTRL + D
Suppose you have a Python code as follows:
Next, you run the program, and while Python is asking for input, you pressed CTRL + D . You get this output:
This is a natural error because CTRL + D sends an end-of-file marker to stop any running process.
The error simply indicates that you’re not passing anything to the input() function.
To handle this error, you can specify a try-except block surrounding the input() call as follows:
Notice that there’s no error received when you press CTRL+D this time. The try-except block handles the EOFError successfully.
2. Calling input() inside a while statement
This error also occurs in a situation where you need to ask for user input, but you don’t know how many times the user will give you input.
For example, you ask the user to input names into a list as follows:
Next, you send one name to the script from the terminal with the following command:
When the input() function is called the second time, there’s no input string to process, so the EOFError is raised.
To resolve this error, you need to surround the code inside the while statement in a try-except block as follows:
This way, the exception when the input string is exhausted will be caught by the try block, and Python can proceed to print the names in the list.
Suppose you run the following command:
When Python runs the input() function for the third time, it hits the end-of-file marker.
The except block gets executed, printing the names list to the terminal. The break statement is used to prevent the while statement from running again.
3. Using an online IDE without supplying the input
When you run Python code using an online IDE, you might get this error because you don’t supply any input using the stdin box.
Here’s an example from ideone.com:
You need to put the input in the stdin box as shown above before you run the code, or you’ll get the EOFError .
Sometimes, online IDEs can’t handle the request for input, so you might want to consider running the code from your computer instead.
Conclusion
This tutorial shows that the EOFError: EOF when reading a line occurs in Python when it sees the end-of-file marker while expecting an input.
To resolve this error, you need to surround the call to input() with a try-except block so that the error can be handled by Python.
I hope this tutorial is helpful. Happy coding!
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EOFError: EOF when reading a line
So as we can see in the pictures above, despite having produced the expected output, our test case fails due to a runtime error EOFError i.e., End of File Error. Let’s understand what is EOF and how to tackle it.
What is EOFError
In Python, an EOFError is an exception that gets raised when functions such as input() or raw_input() in case of python2 return end-of-file (EOF) without reading any input.
When can we expect EOFError
We can expect EOF in few cases which have to deal with input() / raw_input() such as:
Interrupt code in execution using ctrl+d when an input statement is being executed as shown below
Another possible case to encounter EOF is, when we want to take some number of inputs from user i.e., we do not know the exact number of inputs; hence we run an infinite loop for accepting inputs as below, and get a Traceback Error at the very last iteration of our infinite loop because user does not give any input at that iteration
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The code above gives EOFError because the input statement inside while loop raises an exception at last iteration
Do not worry if you don’t understand the code or don’t get context of the code, its just a solution of one of the problem statements on HackerRank 30 days of code challenge which you might want to check
The important part here is, that I used an infinite while loop to accept input which gave me a runtime error.
How to tackle EOFError
We can catch EOFError as any other error, by using try-except blocks as shown below :
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You might want to do something else instead of just printing «EOF» on the console such as:
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In the code above, python exits out of the loop if it encounters EOFError and we pass our test case, the problem due to which this discussion began.
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Hope this is helpful
If you know any other cases where we can expect EOFError, you might consider commenting them below.
Python. Как исправить ошибку EOFError: EOF when reading a line?
Только только притронулся к изучению Python, и уже застрял с ошибкой. Помогите)
- Вопрос задан более двух лет назад
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Простой 5 комментариев
- Вконтакте
В вашем случае, вы вероятно используете Python 2, потому что на Python 3 данный код выполняется корректно.
Так же проблема может заключаться в том, что некоторые терминалы неправильно обрабатывают ввод
(Хотя я сам с таким не сталкивался, но читал что и такое бывает в нашем мире)
- Вконтакте
При использовании input по достижении конца файла или если нажимаете Ctrl+Z и потом Enter, будет сгенерировано исключение EOFError. Чтобы избежать аварийного завершения программы нужно обработать исключение:
try:
a=input(«Enter Your data:»)
print(a)
except EOFError:
print(«Exception handled»)
То есть, когда внутри блока возникнет исключение EOFError, управление будет передано в блок except и после исполнения инструкций в этом блоке программа продолжит нормальную работу.