Ошибка e0f when reading a line - Не ошибается лишь тот, кто ничего не делает!

width, height = map(int, input().split())
def rectanglePerimeter(width, height):
   return ((width + height)*2)
print(rectanglePerimeter(width, height))

Running it like this produces:

% echo "1 2" | test.py
6

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():

width = input()
print(width)
height = input()
print(height)

Running echo "1 2" | test.py produces

1 2
Traceback (most recent call last):
  File "/home/unutbu/pybin/test.py", line 5, in <module>
    height = input()
EOFError: EOF when reading a line

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

width, height = map(int, input().split())

does.

Note, there are other ways to pass input to your program. If you had run test.py in a terminal, then you could have typed 1 and 2 separately with no problem. Or, you could have written a program with pexpect to simulate a terminal, passing 1 and 2 programmatically. Or, you could use argparse to pass arguments on the command line, allowing you to call your program with

test.py 1 2

Источник

When using the input() or raw_input() function in Python, you might see the following error:

EOFError: EOF when reading a line

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:

my_input = input("Enter your name: ")

print("Hello World!")

Next, you run the program, and while Python is asking for input, you pressed CTRL + D. You get this output:

Enter your name: Traceback (most recent call last):
  File "main.py", line 1, in <module>
    my_input = input("Enter your name: ")
EOFError

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:

try:
    my_input = input("Enter your name: ")
except EOFError as e:
    print(e)

print("Hello World!")

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:

names = list()
while True:
    names.append(input("What's your name?: "))
    print(names)

Next, you send one name to the script from the terminal with the following command:

echo "nathan" | python3 main.py

Output:

What's your name?: ['nathan']
What's your name?: Traceback (most recent call last):
  File "main.py", line 11, in <module>
    names.append(input("What's your name?: "))
EOFError: EOF when reading a line

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:

names = list()
while True:
    try:
        names.append(input("What's your name?: "))
    except EOFError as e:
        print(names)
        break

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:

echo "nathan n john" | python3 main.py

Output:

What's your name?: 
What's your name?: 
What's your name?: ['nathan ', ' john']

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! 👍

Источник

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

n=int(input())
if(n>=1 and n<=10**5):
    phone_book={}
    for i in range(n):
        feed=input()
        phone_book[feed.split()[0]]=feed.split()[1]
    while True:
        name=input()
        if name in phone_book.keys():
            print(name,end="")
            print("=",end="")
            print(phone_book[name])
        else:
            print("Not found")

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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 :

try:
    input("Please enter something")
except:
    print("EOF")

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You might want to do something else instead of just printing «EOF» on the console such as:

n=int(input())
if(n>=1 and n<=10**5):
    phone_book={}
    for i in range(n):
        feed=input()
        phone_book[feed.split()[0]]=feed.split()[1]
    while True:
        try:
            name=input()
        except EOFError:
            break
        if name in phone_book.keys():
            print(name,end="")
            print("=",end="")
            print(phone_book[name])
        else:
            print("Not found")

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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…

Hope this is helpful
If you know any other cases where we can expect EOFError, you might consider commenting them below.

Источник

Eoferror: EOF when reading a line occurs when raw_input() or one of the built-in function’s input () hits an end-of-file condition without the program reading any data. It occurs when the user has asked for input but has no input in the input box.

This article explains everything in detail, so keep reading for more information!

Contents

Why Does Eoferror: EOF When Reading a Line Error Occur?
- – Hits an EOF Without Reading Any Data
- – IDLE Passing a Single String to the Script
- – Syntax Error
- – The Input Number Chosen Is Wrong
How To Resolve Eoferror: EOF When Reading a Line Error Message?
- – Use Try-except Blocks
- – Convert Inputs to Ints
- – Use the Correct Command
- – Use Correct Syntax
FAQs
- 1. How To Fix the EOF Error in the Program?
- 2. How Do You Fix Eoferror: EOF When Reading a Line?
Conclusion
Reference

Why Does Eoferror: EOF When Reading a Line Error Occur?

The eoferror: EOF when reading a line error message occurs for multiple reasons, such as: syntax error, no input, or infinite “while” loop. However, there are many other reasons that cause this error message to occur such as hitting an EOF without reading any data.

Some common mistakes of the developers that can lead to this error include:

IDLE passing a single string to the script
Syntax error
The input number chosen is wrong

– Hits an EOF Without Reading Any Data

An eoferror is raised when built-in functions input() or raw_input() hits an EOF, also known as the end-of-file condition. Usually, this happens when the function hits EOF without reading any data.

Sometimes, the programmer experiences this error while using online IDEs. This error occurs when the programmer has asked the user for input but has not provided any input in the program’s input box.

Such a type of error is called Exception Handling. Let’s see the example below, which will generate an EOFError when no input is given to the online IDE.

Program Example:

n = int(input())

print(n * 10)

– IDLE Passing a Single String to the Script

Another reason why this error occurs is that the programmer has written the program in such a way that the IDLE has passed a single string to their script. When a single string is passed to the script, an error occurs.

The first input() is responsible for slurping the entire string in the following example. Notice the program when the programmer puts some print statements in it after the calls to input().

Program Example:

width = input()

print(width)

height = input()

print(height)

Output:

Running (echo “1 2” | test.py) command produces an output of “1 2”

Trackback of the program:

// Traceback (most recent call last):

File “/home/unutbu/pybin/test.py”, line 6, in <module>

height = input()

EOFError: EOF When Reading a Line

Explanation:

See how the first print statement prints the output of the entire string “1 2”, whereas the second call to input() or second print raises an error message to occur. This is because the programmer has used a simple pipe which allows them to pass only one string. Therefore, the programmer can only call the input() function once.

– Syntax Error

The program can show an EOF error message when the programmer tries to print or read a line in the program and has used the wrong syntax. Moreover, various types of EOF errors can occur simply because of minor syntax errors.

Syntax errors can be in a function or a command given to the program. Additionally, minor spelling mistakes are also considered syntax errors.

Some of the common syntax errors that occur when the programmer tries to read a line are listed below:

Eoferror: EOF when reading a line java
Eoferror: EOF when reading a line hackerrank
Eoferror: EOF when reading a line python input
Int(input()) eoferror EOF when reading a line
Docker eoferror: EOF when reading a line
Eoferror: EOF when reading a line zybooks

– The Input Number Chosen Is Wrong

Another possible reason why the programmers get a notification of an EOF error is when they want to take several inputs from a user but do not know the exact number of inputs.

If this is the case, then what is happening here is that the programmer has run an infinite loop for accepting inputs. In return, they get a trackback error at the very last iteration of the infinite loop. This is because the user did not give any input at the iteration.

To understand this concept more, let’s see an example given below.

For example:

0=int(input())

if(o>=2 and 0<=11**6):

phone_book={}

for b in range(o):

feed=input()

phone_book[feed.split()[1]]=feed.split()[2]

while True:

name=input()

if name in phone_book.keys():

print(name,end=””)

print(“=”,end=””)

print(phone_book[name])

else:

print(“Not found”)

Explanation:

After executing this program, the programmer will get an EOFError because the input statement inside the “while” loop has raised an exception at the last iteration. The program will give the programmer a runtime error.

How To Resolve Eoferror: EOF When Reading a Line Error Message?

You can resolve Eoferror: EOF when reading a line error message using multiple possible solutions, such as: using the “try/except” function, correcting the syntax errors or using the correct commands. Before opting for any of the methods, ensure that your code has correct syntax.

Some other solutions are listed below and explained in detail:

– Use Try-except Blocks

In order to resolve the eoferror, the programmer should first try to use the “try-except” block in their program. The program will get an option to give the output without any error at the execution time. Let’s see the example below:

For example:

Try:

width = input()

height = input()

def rectanglePerimeter(height, width):

return ((height + width)*2)

print(rectanglePerimeter(height, width))

except EOFError as e:

print(end=””)

– Convert Inputs to Ints

Try to convert the input() functions to ints. This will help remove the error message as the input could be an integer, and without the “int” function, the program will not execute but instead show an error message.

The syntax used to convert the input to ints is:

width = int(input())

height = int(input())

For example:

Try:

width = int(input())

height = int(input())

def rectanglePerimeter(height, width):

return ((height + width)*2)

print(rectanglePerimeter(height, width))

except EOFError as e:

print(end=””)

– Use the Correct Command

Sometimes the programmer accidentally uses a wrong command, and that causes issues in the program due to which an eoferror error occurs. This is because the command was unable to read the program line. Let’s check the below example to understand how the programmer has used the “break” function to avoid the EOF error.

For example:

p=int(input())

if(p>=2 and p<=11**6):

phone_book={}

for c in range(p):

feed=input()

phone_book[feed.split()[0]]=feed.split()[1]

while True:

Try:

name=input()

except EOFError:

break

if name in phone_book.keys():

print(name,end=””)

print(“=”,end=””)

print(phone_book[name])

else:

print(“Not found”)

– Use Correct Syntax

A syntax error occurs when a command or function is wrong or used incorrectly. Due to EOF syntax errors, the program cannot execute its functions properly while trying to read a program line.

FAQs

1. How To Fix the EOF Error in the Program?

You can fix the EOF error in the program by using the “pass” keyword in the “except” block. The best way to avoid an EOF error message while coding in python or any platform is to catch the exception and pass it using the keyword “pass” in the “except” block.

2. How Do You Fix Eoferror: EOF When Reading a Line?

To fix the eoferror: EOF error when reading a line, you have to use the try() and except() functions in python. Moreover, the questions “how to fix eoferror: EOF when reading a line” and “how do you fix eoferror: EOF when reading a line” are the same with identical solutions.

Conclusion

In this article, we tried to share everything you need to know about the eoferror: EOF when reading a line_. We began with some of the major reasons behind this error and shared various quick yet effective and easy-to-follow methods to fix the error.

Let’s look at some of the key takeaways discussed above for better focus:

This error can be experienced while using online IDEs.
A code can generate an EOFError when no input exists in the online IDE.
Note that the input() returns a string and not an int. Thus, the calculation will fail.

The reader can now resolve their program’s error and work on it smoothly while using this guide as a guide.

Reference

https://stackoverflow.com/questions/17675925/eoferror-eof-when-reading-a-line
https://www.geeksforgeeks.org/handling-eoferror-exception-in-python/#:~:text=EOFError%20is%20raised%20when%20one,input%20in%20the%20input%20box.
https://dev.to/rajpansuriya/eoferror-eof-when-reading-a-line-12fe

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Источник

Before starting how to fix EOF When Reading a Line using Python, it’s crucial to understand what causes it, or what even is it in the first place.

An EOF error occurs when you try to read from the end of a file. This can happen because there are no more lines left, or if your program expected some other value instead.

It might be due for example an encoding mistake made by accident while transferring data over Bluetooth connections etcetera!

EOFError(End Of File Error) is a type of exception handling error that Python raises because of either of the following reasons:

When the input() function is interrupted in both Python 2.7 and Python 3.6+
When the input() function reaches the end of the line unexpectedly in Python 2.7
You forgot to enclose your code within a special statement like a for loop or while loop
You did not close the parentheses properly i.e number of brackets is either more or less than it should be

The BaseException class is the base class of the Exception class which in turn inherits the EOFError class. Technically speaking, EOFError is not an error, but it is an exception.

When the built-in functions such as read() or input() return a string that is empty (unable to read any data), then the EOFError exception is raised.

Or in simple words, EOFError is raised when our program is trying to read or modify something but is unable to do so.

EXAMPLES OF EOFError

# You may also use like int(input())
# or alternative way
n = "10"
print(n * 10)

The code mentioned above will return an EOFError if no input is given to the online IDE, which means that there is no data for the program to work with.

Hence the error.

animals = ["cat", "dog", "mouse", "monkey"]
for i in animals:
    print(i)

In this code, we iterate through the “animals” list successfully but still, the IDE prompts an EOFError. This is because we haven’t put any code within our for-loop.

This is also the case with other statements, meaning that EOFError will be raised if we don’t specify any code within the while-loop, if-else statements, or a function.

To avoid this error we have to write some code, however small it is, within the loop. Or, if we don’t want to specify any code within the statement.

We can use the “pass” statement which is usually used as a placeholder for future code.

print("hello")

This code will also raise an EOFError since the number of parentheses opened and closed are not equal. To tackle this issue simply add a closing bracket at the end of the print statement.

We will be good to go. Another example of the same kind of problem is:

animals = ["cat", "dog", "mouse", "monkey"]

Since the closing square bracket is missing, the IDE will raise an EOFError.

animals = {'mammal':'cat', "fish":"shark"}
print(animals)

The same will be the case with dictionaries if the number of curly brackets is uneven.

Read more: How to Check if File Exists Using Python?

Read file

The most common reason for this is that you have reached the end of the file without reading all of the data.

To fix this, make sure that you read all of the data in the file before trying to access its contents. You can do this by using a loop to read through the file’s contents.

Alternatively, you can use a function like len() to find out how many bytes are in the file so that you can ensure that you read through all of them.

Fix EOFError: EOF When Reading a Line using Python

Conclusion

The statement “SyntaxError: unexpected EOF while parsing” is thrown by the IDE when the interpreter reaches the end of a program before every line of code has been executed.

To solve this error our first step should be to make sure that all statements such as for-loop, while-loop, if statements, etc contain some code. Next, we should make sure that all the parentheses have properly closed.

1. Interrupting code execution with CTRL + D

2. Calling input() inside a while statement

3. Using an online IDE without supplying the input

Conclusion

What is EOFError

When can we expect EOFError

How to tackle EOFError

Why Does Eoferror: EOF When Reading a Line Error Occur?

– Hits an EOF Without Reading Any Data

– IDLE Passing a Single String to the Script

– Syntax Error

– The Input Number Chosen Is Wrong

How To Resolve Eoferror: EOF When Reading a Line Error Message?

– Use Try-except Blocks

– Convert Inputs to Ints

– Use the Correct Command

– Use Correct Syntax

FAQs

1. How To Fix the EOF Error in the Program?

2. How Do You Fix Eoferror: EOF When Reading a Line?

Conclusion

Reference

EXAMPLES OF EOFError

Read file

Fix EOFError: EOF When Reading a Line using Python

Conclusion

1. Interrupting code execution with `CTRL + D`

2. Calling `input()` inside a while statement