How to chek existence of variable JUST in python2?

Question

0.00/5 (No votes)

See more:

hey!
actually I looking for a method to check existence of a variable like bellow:

Python

a = input()
if a:
    #do somthing
else:
    #do something else

but unfortunately it's work just in python3 and don't work in python2(because of the difference between the built-in function

Python

input()

in python2&3.

I want if user enter the ENTER do something else enter something(like string or integer) do something else

Hint:I use the bellow method but it doesn't work.(consider the upper condition.)

What I have tried:

Python

a = input()
if a:
    #do somthing
else:
    #do something else

and

Python

try:
   a = input()
NameErro:
    #do somthing
else:
    #do something else

Posted 16-Jan-17 22:56pm

Member 12953901

Updated 17-Jan-17 18:54pm

Add a Solution

4 solutions

Add a Solution

Add your solution here

Treat my content as plain text, not as HTML

Preview 0

…

Existing Members

Sign in to your account

...or Join us

Download, Vote, Comment, Publish.

Your Email
Password
Forgot your password?

Your Email
This email is in use. Do you need your password?
Optional Password

I have read and agree to the Terms of Service and Privacy Policy
Please subscribe me to the CodeProject newsletters

When answering a question please:

Read the question carefully.
Understand that English isn't everyone's first language so be lenient of bad spelling and grammar.
If a question is poorly phrased then either ask for clarification, ignore it, or edit the question and fix the problem. Insults are not welcome.
Don't tell someone to read the manual. Chances are they have and don't get it. Provide an answer or move on to the next question.

Let's work to help developers, not make them feel stupid.

This content, along with any associated source code and files, is licensed under The Code Project Open License (CPOL)

Richard MacCutchan · Answer 1 · 2017-01-16T23:08:00

Solution 1

See input - Google Search[^].

Posted 16-Jan-17 23:08pm

Richard MacCutchan

Albert Holguin · Answer 2 · 2017-01-17T04:15:00

Solution 2

This explains the differences between the python2 and python3 interpretation of input():
python - What's the difference between raw_input() and input() in python3.x? - Stack Overflow[^]

Posted 17-Jan-17 4:15am

Albert Holguin

TheDarkCyan · Answer 3 · 2017-01-17T17:59:00

Solution 3

Just check if the input isn't non-existant by putting a try/except case!

Python

try:
  a = input()
  #value exists
  print("You entered something!")
except:
  #value does not exist
  print("You didn't enter anything!")

Posted 17-Jan-17 17:59pm

TheDarkCyan

Updated 17-Jan-17 18:07pm

v3

Peter Leow · Answer 4 · 2017-01-17T18:54:00

Solution 4

For python 2.7, use raw_input() instead of input(), e.g.

a = raw_input()
if a=="":
    print "you have not entered anything!"
else:
    print "you have enter {}.".format(a)

Refer: 2. Built-in Functions — Python 2.7.13 documentation[^]

Posted 17-Jan-17 18:54pm

Peter Leow