Re: [Tutor] Global values import scope
Wesley Brooks wrote: Dear Users, I'm using global values to create a unique ID, or name for each instance of a class. If I import the following in one file and test it it works fine. If the following class was imported in two different files run by the same program would each instance of the class have a unique name, or would they only be unique within the scope of the file which contains the import of the bellow class? I believe that, if your program is importing 2 other packages, each of which import some other package, that other doubly-imported package will only be executed once, by whichever one you import first. itemID = 0 class AssemblyItem: def __init__(self): global itemID self.ID = assemblyItem + str(itemID) itemID += 1 I'm 99% sure you can accomplish the same thing with a variable that is global to all instances of the class. something like (may not work): class Foo: itemID = 0 def __init__(self): itemID += 1 HTH, -Luke ___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] Global values import scope
Luke Paireepinart wrote: I believe that, if your program is importing 2 other packages, each of which import some other package, that other doubly-imported package will only be executed once, by whichever one you import first. Yes, that's right. itemID = 0 class AssemblyItem: def __init__(self): global itemID self.ID = assemblyItem + str(itemID) itemID += 1 I'm 99% sure you can accomplish the same thing with a variable that is global to all instances of the class. something like (may not work): class Foo: itemID = 0 def __init__(self): itemID += 1 That should be Foo.itemID += 1; the class namespace is not part of the default name search path. Kent ___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] Global values import scope
Wesley Brooks wrote: Dear Users, I'm using global values to create a unique ID, or name for each instance of a class. If I import the following in one file and test it it works fine. If the following class was imported in two different files run by the same program would each instance of the class have a unique name, or would they only be unique within the scope of the file which contains the import of the bellow class? itemID = 0 class AssemblyItem: def __init__(self): global itemID self.ID = assemblyItem + str(itemID) itemID += 1 That will work fine. When a module is imported twice, the second import received a cached copy of the same module; the module is only instantiated once. The variable itemID will just exist in one place, in the single instance of the module, and AssemblyItems created from different clients will all share the same counter. Kent ___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] Global values import scope
Thanks for your help I tested what you two said as follows and it worked great. Thank you. (Bellow in file TEST_ClassID.py) class AssemblyItem: itemID = 0 def __init__(self): self.ID = assemblyItem + str(AssemblyItem.itemID) AssemblyItem.itemID += 1 def ReturnID(self): return self.ID (Bellow in file TEST_ImportID1.py) from TEST_ClassID import AssemblyItem class Parent1: def __init__(self): self.testList = [] def PrintID(self): self.testList.append(AssemblyItem()) print self.testList[-1].ReturnID() (Bellow in file TEST_ImportID2.py) from TEST_ClassID import AssemblyItem class Parent2: def __init__(self): self.testList = [] def PrintID(self): self.testList.append(AssemblyItem()) print self.testList[-1].ReturnID() (Bellow, the commands run in the python terminal in the same directory) from TEST_ClassID1 import Parent1 from TEST_ClassID2 import Parent2 a = Parent1() b = Parent2() a.PrintID() assemblyItem0 a.PrintID() assemblyItem1 b.PrintID() assemblyItem2 b.PrintID() assemblyItem3 a.PrintID() assemblyItem4 b.PrintID() assemblyItem5 Thanks again for your help. Wesley Brooks. On 24/01/07, Kent Johnson [EMAIL PROTECTED] wrote: Wesley Brooks wrote: Dear Users, I'm using global values to create a unique ID, or name for each instance of a class. If I import the following in one file and test it it works fine. If the following class was imported in two different files run by the same program would each instance of the class have a unique name, or would they only be unique within the scope of the file which contains the import of the bellow class? itemID = 0 class AssemblyItem: def __init__(self): global itemID self.ID = assemblyItem + str(itemID) itemID += 1 That will work fine. When a module is imported twice, the second import received a cached copy of the same module; the module is only instantiated once. The variable itemID will just exist in one place, in the single instance of the module, and AssemblyItems created from different clients will all share the same counter. Kent ___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] Global values import scope
Wesley Brooks wrote: Thanks for your help I tested what you two said as follows and it worked great. Thank you. (Bellow in file TEST_ClassID.py) class AssemblyItem: itemID = 0 def __init__(self): self.ID = assemblyItem + str(AssemblyItem.itemID) AssemblyItem.itemID += 1 def ReturnID(self): return self.ID (Bellow in file TEST_ImportID1.py) from TEST_ClassID import AssemblyItem class Parent1: def __init__(self): self.testList = [] def PrintID(self): self.testList.append(AssemblyItem()) print self.testList[-1].ReturnID() That's a bit convoluted if all you are trying to do is test AssemblyItem. You could just write from TEST_ClassID import AssemblyItem def printID(): item = AssemblyItem() print tem.ReturnID() or even def printID(): print AssemblyItem().ReturnID() Kent ___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
