input error - NameError name is not defined

Question

I am getting an error when I try to run this simple script   input variable   input   Enter your name     print   your name is    input variable    Let s say I type in  dude   the error I am getting is   line 1  in  lt module gt  input variable   input   Enter your name     File   lt string gt    line 1  in  lt module gt  NameError  name  dude  is not defined   I am running these scripts with Python 2 7

User · Answer

TL DR  input function in Python 2 7  evaluates whatever your enter  as a Python expression  If you simply want to read strings  then use raw input function in Python 2 7  which will not evaluate the read strings   If you are using Python 3 x  raw input has been renamed to input  Quoting the Python 3 0 release notes      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        In Python 2 7  there are two functions which can be used to accept user inputs  One is input and the other one is raw input  You can think of the relation between them as follows  input   eval raw input    Consider the following piece of code to understand this better   gt  gt  gt  dude    thefourtheye   gt  gt  gt  input variable   input  Enter your name     Enter your name  dude  gt  gt  gt  input variable  thefourtheye    input accepts a string from the user and evaluates the string in the current Python context  When I type dude as input  it finds that dude is bound to the value thefourtheye and so the result of evaluation becomes thefourtheye and that gets assigned to input variable   If I enter something else which is not there in the current python context  it will fail will the NameError    gt  gt  gt  input  Enter your name     Enter your name  dummy Traceback  most recent call last     File   lt input gt    line 1  in  lt module gt    File   lt string gt    line 1  in  lt module gt  NameError  name  dummy  is not defined   Security considerations with Python 2 7 s input   Since whatever user types is evaluated  it imposes security issues as well  For example  if you have already loaded os module in your program with import os  and then the user types in  os remove   etc hosts     this will be evaluated as a function call expression by python and it will be executed  If you are executing Python with elevated privileges   etc hosts file will be deleted  See  how dangerous it could be   To demonstrate this  let s try to execute input function again    gt  gt  gt  dude    thefourtheye   gt  gt  gt  input  Enter your name     Enter your name  input  Enter your name again     Enter your name again  dude   Now  when input  Enter your name     is executed  it waits for the user input and the user input is a valid Python function invocation and so that is also invoked  That is why we are seeing Enter your name again  prompt again   So  you are better off with raw input function  like this  input variable   raw input  Enter your name       If you need to convert the result to some other type  then you can use appropriate functions to convert the string returned by raw input  For example  to read inputs as integers  use the int function  like shown in this answer   In python 3 x  there is only one function to get user inputs and that is called input  which is equivalent to Python 2 7 s raw input

User · Answer

You can change which python you re using with your IDE  if you ve already downloaded python 3 x it shouldn t be too hard to switch  But your script works fine on python 3 x  I would just change  print   your name is    input variable    to  print   your name is   input variable    Because with the comma it prints with a whitespace in between your name is and whatever the user inputted  AND  if you re using 2 7 just use raw input instead of input

User · Answer

You are running Python 2  not Python 3   For this to work in Python 2  use raw input   input variable   raw input   Enter your name     print   your name is    input variable

User · Answer

You should use raw input because you are using python-2 7  When you use input   on a variable  for example  s   input  Name       it will execute the command ON the Python environment without saving what you wrote on the variable  s  and create an error if what you wrote is not defined   raw input   will save correctly what you wrote on the variable  for example  f   raw input  Name        and it will not execute it in the Python environment without creating any possible error    input variable   raw input  Enter Your Name      print  Your Name Is         input variable

User · Answer

I also encountered this issue with a module that was supposed to be compatible for python 2 7 and 3 7  what i found to fix the issue was importing   from six moves import input   this fixed the usability for both interpreters   you can read more about the six library here

User · Answer

There are two ways to fix these issues    1st is simple without code change that is run your script by Python3   if you still want to run on python2 then after running your python script  when you are entering the input keep in mind   if you want to enter string then just start typing down with  input goes with double-quote  and it will work in python2 7 and  if you want to enter character then use the input with a single quote like  your input goes here  if you want to enter number not an issue you simply type the number  2nd way is with code  changes use the below import and run with any version of python   from six moves import input Use raw input   function instead of input   function in your code with any import sanitise your code with str   function like str input    and then assign to any variable    As error implies  name  dude  is not defined  i e  for python  dude  become variable here and it s not having any value of python defined type assignedso only its crying like baby so if we define a  dude  variable and assign any value and pass to it  it will work but that s not what we want as we don t know what user will enter and moreover we want to capture the user input      Fact about these method    input   function  This function takes the value and type of the input you enter as it is without modifying it type  raw input     function  This function explicitly converts the input you give into type string          Note  The vulnerability in input   method lies in the fact that   the variable accessing the value of input can be accessed by anyone   just by using the name of variable or method

User · Answer

Good contributions the previous ones   import sys  print sys version   def ingreso nombre       print  Hi    nombre  type nombre    def bienvenida nombre       print  Hi   nombre    bye     nombre   raw input  Enter your name      ingreso nombre  bienvenida nombre    Works in Python 2 and 3  try  input   raw input except NameError  pass print input  Your name        Enter your name  Joe   Hi     Joe    lttype  str  gt  Hi Joe  bye   Your name  Joe Joe   Thanks

User · Answer

For python 3 and above  s   raw input     it will solve the problem on pycharm IDE if you are solving on online site exactly hackerrank then use   s   input

User · Answer

input variable   input   Enter your name     print   your name is    input variable    You have to enter input in either single or double quotes  Ex  dude  - gt  correct      dude - gt  not correct

User · Answer

For anyone else that may run into this issue  turns out that even if you include    usr bin env python3 at the beginning of your script  the shebang is ignored if the file isn t executable   To determine whether or not your file is executable    run   filename py from the command line if you get -bash    filename py  Permission denied  run chmod a x filename py run   filename py again   If you ve included import sys  print sys version  as Kevin suggested  you ll now see that the script is being interpreted by python3

User · Answer

Here is an input function which is compatible with both Python 2 7 and Python 3    Slightly modified answer by  Hardian  to avoid UnboundLocalError  local variable  input  referenced before assignment error def input compatible prompt None       try          input func   raw input     except NameError          input func   input     return input func prompt

User · Answer

You could either do   x   raw input  enter your name   print  your name is  s     x   or   x   str input  enter your name    print  your name is  s    x

User · Answer

Since you are writing for Python 3 x  you ll want to begin your script with      usr bin env python3   If you use      usr bin env python   It will default to Python 2 x  These go on the first line of your script  if there is nothing that starts with     aka the shebang    If your scripts just start with      python   Then you can change it to      python3   Although this shorter formatting is only recognized by a few programs  such as the launcher  so it is not the best choice    The first two examples are much more widely used and will help ensure your code will work on any machine that has Python installed

User · Answer

We are using the following that works both python 2 and python 3   Works in Python 2 and 3  try  input   raw input except NameError  pass print input  Enter your name

User · Answer

Try using raw input rather than input if you simply want to read strings  print  quot Enter your name   quot   x   raw input   print  quot Hello   quot  x

[python] input() error - NameError: name '...' is not defined

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