Python 3: EOF when reading a line (Sublime Text 2 is angry)

while True:
    reply = input('Enter text')
    if reply == 'stop': break
    print(reply.upper())

The result was:

Enter text:Traceback (most recent call last):
  File "C:\PythonProjects\5.py", line 2, in <module>
    reply = input('Enter text:')
EOFError: EOF when reading a line
[Finished in 0.2s with exit code 1]

It is only in Sublime Text 2. I tried IDLE, tried command line, everything is perfect. Why should Subleme shout at me?

By the way, maybe you could also explain my what EOF may mean in such situation. Of course, I have read in the documentation, that if EOF is read from input, the appropriate error is raised. I would like to model this situation. Is input only about the keyboard? If yes, what combination of keys should I input to get EOF?

Thank you in advance.

Solution 1:

I had the same problem. The problem with the Sublime Text's default console is that it does not support input.

To solve it, you have to install a package called SublimeREPL. SublimeREPL provides a Python interpreter which accepts input.

There is an article that explains the solution in detail.

GitHub page for SublimeREPL

Solution 2:

help(input) shows what keyboard shortcuts produce EOF, namely, Unix: Ctrl-D, Windows: Ctrl-Z+Return:

input([prompt]) -> string

Read a string from standard input. The trailing newline is stripped. If the user hits EOF (Unix: Ctl-D, Windows: Ctl-Z+Return), raise EOFError. On Unix, GNU readline is used if enabled. The prompt string, if given, is printed without a trailing newline before reading.

You could reproduce it using an empty file:

$ touch empty
$ python3 -c "input()" < empty
Traceback (most recent call last):
  File "<string>", line 1, in <module>
EOFError: EOF when reading a line

You could use /dev/null or nul (Windows) as an empty file for reading. os.devnull shows the name that is used by your OS:

$ python3 -c "import os; print(os.devnull)"
/dev/null

Note: input() happily accepts input from a file/pipe. You don't need stdin to be connected to the terminal:

$ echo abc | python3 -c "print(input()[::-1])"
cba

Either handle EOFError in your code:

try:
    reply = input('Enter text')
except EOFError:
    break

Or configure your editor to provide a non-empty input when it runs your script e.g., by using a customized command line if it allows it: python3 "%f" < input_file

Solution 3:

EOF is a special out-of-band signal which means the end of input. It's not a character (though in the old DOS days, 0x1B acted like EOF), but rather a signal from the OS that the input has ended.

On Windows, you can "input" an EOF by pressing Ctrl+Z at the command prompt. This signals the terminal to close the input stream, which presents an EOF to the running program. Note that on other OSes or terminal emulators, EOF is usually signalled using Ctrl+D.

As for your issue with Sublime Text 2, it seems that stdin is not connected to the terminal when running a program within Sublime, and so consequently programs start off connected to an empty file (probably nul or /dev/null). See also Python 3.1 and Sublime Text 2 error.