Modifying global variable with same name as local variable












20















Suppose I have a global variable a. And within a function definition, we also have a local variable named a. Is there any way to assign the value of the global variable to that of the local variable?



a = 'foo'



def my_func(a = 'bar'):

    # how to set global a to value of the local a?





python global-variables







share|improve this question

























  • use 'global a' statement within the function definition?

    – newtover
    Apr 19 '12 at 20:13











  • @newtover: But then I can't access the value of the local a in order to assign it to the global one.

    – tskuzzy
    Apr 19 '12 at 20:15






  • 3





    WHY???!!1!11one|11!1ELEVE||1!?. To start, using globals is a bad practice, add a parameter to your func or make a class. Second, why would you want to use the same variable name in different contexts and relate their content. Can you try harder in making your code more ugly and confusing?

    – KurzedMetal
    Apr 19 '12 at 20:19






  • 3





    This is exactly why using global variables is discouraged. Even if there is a way to do this, you shouldn't do it. Change the local variable name, or -- better yet -- don't use a global variable.

    – senderle
    Apr 19 '12 at 20:20






  • 1





    A bit late to the party, but whenever I hit the local/global collision issue, I use an empty class as a namespace container (class Container(): pass, settings = Container(), settings.a = 'foo') and store my global variables in there. It's both mutable and distinguishable: if var1 is None: var1 = settings.var1, else: settings.var1 = var1 and so on.

    – Nisan.H
    May 9 '12 at 20:34
















20















Suppose I have a global variable a. And within a function definition, we also have a local variable named a. Is there any way to assign the value of the global variable to that of the local variable?



a = 'foo'



def my_func(a = 'bar'):

    # how to set global a to value of the local a?





python global-variables







share|improve this question

























  • use 'global a' statement within the function definition?

    – newtover
    Apr 19 '12 at 20:13











  • @newtover: But then I can't access the value of the local a in order to assign it to the global one.

    – tskuzzy
    Apr 19 '12 at 20:15






  • 3





    WHY???!!1!11one|11!1ELEVE||1!?. To start, using globals is a bad practice, add a parameter to your func or make a class. Second, why would you want to use the same variable name in different contexts and relate their content. Can you try harder in making your code more ugly and confusing?

    – KurzedMetal
    Apr 19 '12 at 20:19






  • 3





    This is exactly why using global variables is discouraged. Even if there is a way to do this, you shouldn't do it. Change the local variable name, or -- better yet -- don't use a global variable.

    – senderle
    Apr 19 '12 at 20:20






  • 1





    A bit late to the party, but whenever I hit the local/global collision issue, I use an empty class as a namespace container (class Container(): pass, settings = Container(), settings.a = 'foo') and store my global variables in there. It's both mutable and distinguishable: if var1 is None: var1 = settings.var1, else: settings.var1 = var1 and so on.

    – Nisan.H
    May 9 '12 at 20:34














20












20








20


6






Suppose I have a global variable a. And within a function definition, we also have a local variable named a. Is there any way to assign the value of the global variable to that of the local variable?



a = 'foo'



def my_func(a = 'bar'):

    # how to set global a to value of the local a?





python global-variables







share|improve this question
















Suppose I have a global variable a. And within a function definition, we also have a local variable named a. Is there any way to assign the value of the global variable to that of the local variable?



a = 'foo'



def my_func(a = 'bar'):

    # how to set global a to value of the local a?





python global-variables




python global-variables






share|improve this question















share|improve this question













share|improve this question




share|improve this question








edited Apr 19 '12 at 20:16







tskuzzy

















asked Apr 19 '12 at 20:10









tskuzzytskuzzy

28.5k1256123




28.5k1256123













  • use 'global a' statement within the function definition?

    – newtover
    Apr 19 '12 at 20:13











  • @newtover: But then I can't access the value of the local a in order to assign it to the global one.

    – tskuzzy
    Apr 19 '12 at 20:15






  • 3





    WHY???!!1!11one|11!1ELEVE||1!?. To start, using globals is a bad practice, add a parameter to your func or make a class. Second, why would you want to use the same variable name in different contexts and relate their content. Can you try harder in making your code more ugly and confusing?

    – KurzedMetal
    Apr 19 '12 at 20:19






  • 3





    This is exactly why using global variables is discouraged. Even if there is a way to do this, you shouldn't do it. Change the local variable name, or -- better yet -- don't use a global variable.

    – senderle
    Apr 19 '12 at 20:20






  • 1





    A bit late to the party, but whenever I hit the local/global collision issue, I use an empty class as a namespace container (class Container(): pass, settings = Container(), settings.a = 'foo') and store my global variables in there. It's both mutable and distinguishable: if var1 is None: var1 = settings.var1, else: settings.var1 = var1 and so on.

    – Nisan.H
    May 9 '12 at 20:34



















  • use 'global a' statement within the function definition?

    – newtover
    Apr 19 '12 at 20:13











  • @newtover: But then I can't access the value of the local a in order to assign it to the global one.

    – tskuzzy
    Apr 19 '12 at 20:15






  • 3





    WHY???!!1!11one|11!1ELEVE||1!?. To start, using globals is a bad practice, add a parameter to your func or make a class. Second, why would you want to use the same variable name in different contexts and relate their content. Can you try harder in making your code more ugly and confusing?

    – KurzedMetal
    Apr 19 '12 at 20:19






  • 3





    This is exactly why using global variables is discouraged. Even if there is a way to do this, you shouldn't do it. Change the local variable name, or -- better yet -- don't use a global variable.

    – senderle
    Apr 19 '12 at 20:20






  • 1





    A bit late to the party, but whenever I hit the local/global collision issue, I use an empty class as a namespace container (class Container(): pass, settings = Container(), settings.a = 'foo') and store my global variables in there. It's both mutable and distinguishable: if var1 is None: var1 = settings.var1, else: settings.var1 = var1 and so on.

    – Nisan.H
    May 9 '12 at 20:34

















use 'global a' statement within the function definition?

– newtover
Apr 19 '12 at 20:13





use 'global a' statement within the function definition?

– newtover
Apr 19 '12 at 20:13













@newtover: But then I can't access the value of the local a in order to assign it to the global one.

– tskuzzy
Apr 19 '12 at 20:15





@newtover: But then I can't access the value of the local a in order to assign it to the global one.

– tskuzzy
Apr 19 '12 at 20:15




3




3





WHY???!!1!11one|11!1ELEVE||1!?. To start, using globals is a bad practice, add a parameter to your func or make a class. Second, why would you want to use the same variable name in different contexts and relate their content. Can you try harder in making your code more ugly and confusing?

– KurzedMetal
Apr 19 '12 at 20:19





WHY???!!1!11one|11!1ELEVE||1!?. To start, using globals is a bad practice, add a parameter to your func or make a class. Second, why would you want to use the same variable name in different contexts and relate their content. Can you try harder in making your code more ugly and confusing?

– KurzedMetal
Apr 19 '12 at 20:19




3




3





This is exactly why using global variables is discouraged. Even if there is a way to do this, you shouldn't do it. Change the local variable name, or -- better yet -- don't use a global variable.

– senderle
Apr 19 '12 at 20:20





This is exactly why using global variables is discouraged. Even if there is a way to do this, you shouldn't do it. Change the local variable name, or -- better yet -- don't use a global variable.

– senderle
Apr 19 '12 at 20:20




1




1





A bit late to the party, but whenever I hit the local/global collision issue, I use an empty class as a namespace container (class Container(): pass, settings = Container(), settings.a = 'foo') and store my global variables in there. It's both mutable and distinguishable: if var1 is None: var1 = settings.var1, else: settings.var1 = var1 and so on.

– Nisan.H
May 9 '12 at 20:34





A bit late to the party, but whenever I hit the local/global collision issue, I use an empty class as a namespace container (class Container(): pass, settings = Container(), settings.a = 'foo') and store my global variables in there. It's both mutable and distinguishable: if var1 is None: var1 = settings.var1, else: settings.var1 = var1 and so on.

– Nisan.H
May 9 '12 at 20:34












4 Answers
4






active

oldest

votes


















29














Use built-in function globals().




globals()



Return a dictionary representing the current global symbol
table. This is always the dictionary of the current module (inside a
function or method, this is the module where it is defined, not the
module from which it is called).




a = 'foo'



def my_func(a = 'bar'):

    globals()['a'] = a


BTW, it's worth mentioning that a global is only "global" within the scope of a module.






share|improve this answer


























  • Works perfectly! Thank you!

    – tskuzzy
    Apr 19 '12 at 20:24



















1














Let python know that you want the global version;



def my_func():

    global a

    a = 'bar'





share|improve this answer
























  • Sorry, rephrased the question. I want to set the global a to the value of the local a.

    – tskuzzy
    Apr 19 '12 at 20:14



















0














>>> a = 'foo'

>>> def my_func(a='bar'):

...     return globals()['a']

...

>>> my_func()

'foo'





share|improve this answer































    0














    Don't muddle global and local namespaces to begin with. Always try and use a local variable versus a global one when possible. If you must share variables between scopes you can still pass the variables without need for a global placeholder. Local variables are also referenced much more efficiently accessed than globals.



    A few links:



    Sharing Variables in Python



    Variable performance






    share|improve this answer

























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      4 Answers
      4






      active

      oldest

      votes








      4 Answers
      4






      active

      oldest

      votes









      active

      oldest

      votes






      active

      oldest

      votes









      29














      Use built-in function globals().




      globals()



      Return a dictionary representing the current global symbol
      table. This is always the dictionary of the current module (inside a
      function or method, this is the module where it is defined, not the
      module from which it is called).




      a = 'foo'
      

      
def my_func(a = 'bar'):
      
    globals()['a'] = a


      BTW, it's worth mentioning that a global is only "global" within the scope of a module.






      share|improve this answer


























      • Works perfectly! Thank you!

        – tskuzzy
        Apr 19 '12 at 20:24
















      29














      Use built-in function globals().




      globals()



      Return a dictionary representing the current global symbol
      table. This is always the dictionary of the current module (inside a
      function or method, this is the module where it is defined, not the
      module from which it is called).




      a = 'foo'
      

      
def my_func(a = 'bar'):
      
    globals()['a'] = a


      BTW, it's worth mentioning that a global is only "global" within the scope of a module.






      share|improve this answer


























      • Works perfectly! Thank you!

        – tskuzzy
        Apr 19 '12 at 20:24














      29












      29








      29







      Use built-in function globals().




      globals()



      Return a dictionary representing the current global symbol
      table. This is always the dictionary of the current module (inside a
      function or method, this is the module where it is defined, not the
      module from which it is called).




      a = 'foo'
      

      
def my_func(a = 'bar'):
      
    globals()['a'] = a


      BTW, it's worth mentioning that a global is only "global" within the scope of a module.






      share|improve this answer















      Use built-in function globals().




      globals()



      Return a dictionary representing the current global symbol
      table. This is always the dictionary of the current module (inside a
      function or method, this is the module where it is defined, not the
      module from which it is called).




      a = 'foo'
      

      
def my_func(a = 'bar'):
      
    globals()['a'] = a


      BTW, it's worth mentioning that a global is only "global" within the scope of a module.







      share|improve this answer














      share|improve this answer



      share|improve this answer








      edited Jan 18 at 18:45









      Rob Stewart

      72




      72










      answered Apr 19 '12 at 20:21









      vartecvartec

      95.5k26177219




      95.5k26177219













      • Works perfectly! Thank you!

        – tskuzzy
        Apr 19 '12 at 20:24



















      • Works perfectly! Thank you!

        – tskuzzy
        Apr 19 '12 at 20:24

















      Works perfectly! Thank you!

      – tskuzzy
      Apr 19 '12 at 20:24





      Works perfectly! Thank you!

      – tskuzzy
      Apr 19 '12 at 20:24













      1














      Let python know that you want the global version;



      def my_func():
      
    global a
      
    a = 'bar'





      share|improve this answer
























      • Sorry, rephrased the question. I want to set the global a to the value of the local a.

        – tskuzzy
        Apr 19 '12 at 20:14
















      1














      Let python know that you want the global version;



      def my_func():
      
    global a
      
    a = 'bar'





      share|improve this answer
























      • Sorry, rephrased the question. I want to set the global a to the value of the local a.

        – tskuzzy
        Apr 19 '12 at 20:14














      1












      1








      1







      Let python know that you want the global version;



      def my_func():
      
    global a
      
    a = 'bar'





      share|improve this answer













      Let python know that you want the global version;



      def my_func():
      
    global a
      
    a = 'bar'






      share|improve this answer












      share|improve this answer



      share|improve this answer










      answered Apr 19 '12 at 20:13









      AlGAlG

      10.4k43447




      10.4k43447













      • Sorry, rephrased the question. I want to set the global a to the value of the local a.

        – tskuzzy
        Apr 19 '12 at 20:14



















      • Sorry, rephrased the question. I want to set the global a to the value of the local a.

        – tskuzzy
        Apr 19 '12 at 20:14

















      Sorry, rephrased the question. I want to set the global a to the value of the local a.

      – tskuzzy
      Apr 19 '12 at 20:14





      Sorry, rephrased the question. I want to set the global a to the value of the local a.

      – tskuzzy
      Apr 19 '12 at 20:14











      0














      >>> a = 'foo'
      
>>> def my_func(a='bar'):
      
...     return globals()['a']
      
...
      
>>> my_func()
      
'foo'





      share|improve this answer




























        0














        >>> a = 'foo'
        
>>> def my_func(a='bar'):
        
...     return globals()['a']
        
...
        
>>> my_func()
        
'foo'





        share|improve this answer


























          0












          0








          0







          >>> a = 'foo'
          
>>> def my_func(a='bar'):
          
...     return globals()['a']
          
...
          
>>> my_func()
          
'foo'





          share|improve this answer













          >>> a = 'foo'
          
>>> def my_func(a='bar'):
          
...     return globals()['a']
          
...
          
>>> my_func()
          
'foo'






          share|improve this answer












          share|improve this answer



          share|improve this answer










          answered Apr 19 '12 at 20:23









          KurzedMetalKurzedMetal

          9,21932952




          9,21932952























              0














              Don't muddle global and local namespaces to begin with. Always try and use a local variable versus a global one when possible. If you must share variables between scopes you can still pass the variables without need for a global placeholder. Local variables are also referenced much more efficiently accessed than globals.



              A few links:



              Sharing Variables in Python



              Variable performance






              share|improve this answer






























                0














                Don't muddle global and local namespaces to begin with. Always try and use a local variable versus a global one when possible. If you must share variables between scopes you can still pass the variables without need for a global placeholder. Local variables are also referenced much more efficiently accessed than globals.



                A few links:



                Sharing Variables in Python



                Variable performance






                share|improve this answer




























                  0












                  0








                  0







                  Don't muddle global and local namespaces to begin with. Always try and use a local variable versus a global one when possible. If you must share variables between scopes you can still pass the variables without need for a global placeholder. Local variables are also referenced much more efficiently accessed than globals.



                  A few links:



                  Sharing Variables in Python



                  Variable performance






                  share|improve this answer















                  Don't muddle global and local namespaces to begin with. Always try and use a local variable versus a global one when possible. If you must share variables between scopes you can still pass the variables without need for a global placeholder. Local variables are also referenced much more efficiently accessed than globals.



                  A few links:



                  Sharing Variables in Python



                  Variable performance







                  share|improve this answer














                  share|improve this answer



                  share|improve this answer








                  edited Apr 23 '12 at 13:48

























                  answered Apr 19 '12 at 20:25









                  PenguinCoderPenguinCoder

                  3,6612036




                  3,6612036






























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