Creating an Instance of a Class with a variable in Python

Question

I m trying to create a game for my little sister  It is a Virtual Pet sort of thing and the Pet has toys to play with   I created a class Toy and want to create a function  getNewToy name  data1  data2  data3  data4  data5    I want this function to create a new instance of the class Toy  and I want the function to be able to be called multiple times each time creating a new instance   In my experience you create an instance with   class Toy      def   init   self  name  data1  data2  data3  data4  data5           pass  myToy   Toy myToy  1  2  3  4  5    then to use methods from the class with   myToy method1     Seeing as I want to have the ability to have multiple toys  each with a playWith   method I want the instance to reflect the name of the Toy each time one is called   I want the instance to be different each time I call the method getNewToy       and the instance to reflect the name

User · Answer

I think you can use eval  Something like this  def toclass strcls       return eval strcls

User · Answer

If you just want to pass a class to a function  so that this function can create new instances of that class  just treat the class like any other value you would give as a parameter   def printinstance someclass     print someclass     Result    gt  gt  gt  printinstance list      gt  gt  gt  printinstance dict

User · Answer

You can create variable like this   x   10  print x    Or this   globals    y     100 print y    Lets create a new class   class Foo object       def   init   self           self name    John    You can create class instance this way   instance name 1   Foo     Or this way   globals    instance name 2     Foo     Lets create a function   def create new instance class name instance name       globals   instance name    class name       print  Class instance      created   format instance name     Call a function   create new instance Foo  new instance    Class instance  new instance  created  print new instance name   John   Also we can write generator function   def create instance class name instance name       count   0     while True          name   instance name   str count          globals   name    class name           count    1         print  Class instance      format name           yield True  generator instance   create instance Foo  instance      for i in range 5       next generator instance    out  Class instance  instance 0  Class instance  instance 1  Class instance  instance 2  Class instance  instance 3  Class instance  instance 4  print instance 0 name   john print instance 1 name   john print instance 2 name   john print instance 3 name   john print instance 4 name   john   print instance 5 name   error   we only created 5 instances     next generator instance   Class instance  instance 5 print instance 5 name   John  Now it works

User · Answer

Rather than use multiple classes or class inheritance  perhaps a single Toy class that knows what  kind  it is   class Toy      num   0     def   init   self  name  kind   args           self name   name         self kind   kind         self data   args         self num   Toy num         Toy num    1      def   repr   self           return     join  self name self kind str self num         def playWith self           print self  def getNewToy name  kind       return Toy name  kind   t1   Toy  Suzie    doll   t2   getNewToy  Jack    robot   print t1 t2 playWith     Running it     python toy py  Suzie doll 0 Jack robot 1   As you can see  getNewToy is really unnecessary   Now you can modify playWith to check the value of self kind and change behavior  you can redefine playWith to designate a playmate   def playWith self  who None       if who   pass     print self  t1 playWith t2

User · Answer

This is a very strange question to ask  specifically of python  so being more specific will definitely help me answer it   As is  I ll try to take a stab at it   I m going to assume what you want to do is create a new instance of a datastructure and give it a variable   For this example I ll use the dictionary data structure and the variable mydictionary   mydictionary   dict     This will create a new instance of the dictionary data structure and place it in the variable named mydictionary   Alternatively the dictionary constructor can also take arguments   mydictionary   dict    sape   4139     guido   4127     jack   4098      Finally  python will attempt to figure out what data structure I mean from the data I give it  IE  mydictionary     jack   4098   sape   4139    These examples were taken from Here

User · Answer

Let s say you have three classes  Enemy1  Enemy2  Enemy3  This is how you instantiate them directly   Enemy1   Enemy2   Enemy3     but this will also work   x   Enemy1 x   x   Enemy2 x   x   Enemy3 x     Is this what you meant

User · Answer

Given your edit i assume you have the class name as a string and want to instantiate the class  Just use a dictionary as a dispatcher   class Foo object       pass  class Bar object       pass  dispatch dict     Foo   Foo   Bar   Bar  dispatch dict  Foo       returns an instance of Foo

User · Answer

If you haven t found it yet  here is Dive into Python s chapter on object-oriented programming   Here are some more examples  scroll to BankAccount     You can call a class directly to create an instance  Parameters are passed to the   init   method   class Tamago object       def   init   self  name           self name   name  imouto   Tamago  imouto   oba   Tamago  oba   oba name    oba  imouto name    imouto

[python] Creating an Instance of a Class with a variable in Python

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