CODEWITHSUNDEEP
pythonpython-2.7
somesh
somesh

Reputation: 87

NameError while using eval() function

I'm trying to call a module from another module by using the eval() function it is calling successfully but in console output i am getting error message like "NameError: name 'Login_CSA' is not defined"

I have written the code like this

In sample.py module 

import ReferenceUnits

def calling():
    str='Login_CSA'
    eval(str)

calling()

In ReferenceUnits.py 

import Login_CSA

and in Login_CSA.py I have written

def Hai():
    print "hello this is somesh"
    print 'hi welcome to Hai function'

Hai()

It is executing but finally getting error message like "NameError: name 'Login_CSA' is not defined"

Why is this so?

Upvotes: 1

Views: 8589

Answers (3)

glglgl
glglgl

Reputation: 91049

If you

  • import Login_CSA in ReferenceUnits.py,
  • import ReferenceUnits in sample.py,

you have to access

  • ReferenceUnits by using ReferenceUnits,
  • Login_CSA by using ReferenceUnits.Login_CSA and
  • Hai by using ReferenceUnits.Login_CSA.Hai.

So you can do

def calling():
    str='ReferenceUnits.Login_CSA.hai'
    eval(str)() # the () is essential, as otherwise, nothing gets called.

calling()

Upvotes: 1

Nils Werner
Nils Werner

Reputation: 36765

My guess is you are trying to "include and evaluate a second script" like you would do in PHP. In Python, when you import a file, all the methods become available in your local script. So instead of evaling the file you would just call the method from it.

import ReferenceUnits
import Login_CSA

def calling():
    Login_CSA.Hai()

if __name__ == "__main__":
    calling()

and change Login_CSA.py to

def Hai():
    print "hello this is somesh"
    print 'hi welcome to Hai function'

if __name__ == "__main__":
    Hai()

the if __name__ == "__main__": block is important as it prevents imported scripts from executing code during import (you only very rarely want to execute code on import).

Upvotes: 2

Deelaka
Deelaka

Reputation: 13693

The function eval() executes valid python expressions such as:

>>> x = 1
>>> print eval('x+1')
2

In your case the eval() function looks for the variable Login_CSA which simply doesn't exist, So it returns NameError: name 'Login_CSA' is not defined

Upvotes: 1

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