difference between python2 and python3 - int() and input()

Question

I wrote below python code. And I found that python2 and python3 has totally difference running result for input of 1.1. Why is there such difference between python2 and pyth

Answer 1

The issue is intput() converts the value to an number for python2 and a string for python 3.

int() of a non int string returns an error, while int() of a float does not.

Convert the input value to a float using either:

value=float(input())

or, better (safer) yet

position=int(float(value))

EDIT: And best of all, avoid using input since it uses an eval and is unsafe. As Tadhg suggested, the best solution is:

#At the top:
try:
    #in python 2 raw_input exists, so use that
    input = raw_input
except NameError:
    #in python 3 we hit this case and input is already raw_input
    pass

...
    try:
        #then inside your try block, convert the string input to an number(float) before going to an int
        position = int(float(value))

From the Python Docs:

PEP 3111: raw_input() was renamed to input(). That is, the new input() function reads a line from sys.stdin and returns it with the trailing newline stripped. It raises EOFError if the input is terminated prematurely. To get the old behavior of input(), use eval(input()).

Answer 2

Please check the Python 3 release notes. In particular, the input() function (which is considered dangerous) was removed. In its stead, the safer raw_input() function was renamed to input().

In order to write code for both versions, only rely on raw_input(). Add the following to the top of your file:

try:
    # replace unsafe input() function
    input = raw_input
except NameError:
    # raw_input doesn't exist, the code is probably
    # running on Python 3 where input() is safe
    pass

BTW: Your example code isn't minimal. If you had further reduced the code, you would have found that in one case int() operates on a float and in the other on a str which would then have brought you to the different things that input() returns. A look at the docs would then have given you the final hint.