Convert String to Python Class Object

Convert string to Python class object?

Warning: eval() can be used to execute arbitrary Python code. You should never use eval() with untrusted strings. (See Security of Python's eval() on untrusted strings?)

This seems simplest.

>>> class Foo(object):
...     pass
... 
>>> eval("Foo")
<class '__main__.Foo'>

Convert type string object to type class object in python

I found a solution. I have made a list of all enemy's along side their name. Then I return the index of the corresponding value to the enemies name. Below is what I came up with.

Enemy creation:

boss = EnemyCreator('Charles Hammerdick', 'boss', 10000, 200)
npc_list.append(boss)
npc_list.append(boss.name)

attack function:

def attack(enemy):
for thing in npc_list:
    if str(enemy) in str(thing):
        enemy = (npc_list[npc_list.index(thing) - 1])
        enemy.health = enemy.health - playerChar.ap
        if enemy.health > 0:
            playerChar.health = playerChar.health - enemy.ap
            return ('You attacked ' + enemy.name + '. ' + str(enemy.health) + ' life remaining. \n'
                    + enemy.name + ' attacks back! You take ' + str(enemy.ap) + ' damage. You have ' + str(playerChar.health)
                    + ' remaining!')
        if enemy.health <= 0:
            return enemy.name + ' has been defeated!'
        if playerChar.health <= 0:
            return 'You died idiot.'

python: Convert string to class object

You need the function getattr for this:

getattr(temp_text, 'a')

String to Object in Python

You are looking at ways of serialising objects; this is a very standard problem. pickle is the standard solution, and you should look into it first. If you want to make a class pickleable, you need to define some custom methods on it, and ensure the module in which it is defined can be found on both the source and destination computers. Then you can pickle.dumps(obj) which will return a string, and pickle.loads(my_str) to rebuild the object.

Other options include marshal (low-level) and json (standard for web data).

How do I convert string to object type without using eval() in for loop?

Store the objects in a dict from their "name" to the instances (it's better to explicitly maintain such a mapping instead of falling to the trap of using locals() or globals()).

A = Testclass()
B = Testclass()

objects = {"A": A, "B": B}
seq = ["AB", "BA", "AB"]

for val in seq:
    obj1, obj2 = list(val)
    objects[obj1].change(objects[obj2])

BTW, it's possible to unpack a string directly without list:

ob1, obj2 = val

How to convert string to class sub-attribute with Python

The operator.attrgetter function does this:

class Foo: pass
f = Foo()
f.bar = Foo()
f.bar.baz = Foo()
f.bar.baz.quux = "Found me!"

import operator
print operator.attrgetter("bar.baz.quux")(f)     # prints "Found me!"

Get python class object from string

You want to use the importlib module to handle loading of modules like this, then simply use getattr() to get the classes.

For example, say I have a module, somemodule.py which contains the class Test:

import importlib

cls = "somemodule.Test"
module_name, class_name = cls.split(".")

somemodule = importlib.import_module(module_name)

print(getattr(somemodule, class_name))

Gives me:

<class 'somemodule.Test'>

It's trivial to add in things like packages:

cls = "test.somemodule.Test"
module_name, class_name = cls.rsplit(".", 1)

somemodule = importlib.import_module(module_name)

And it will not import a module/package if it's already been imported, so you can happily do this without keeping track of loading modules:

import importlib

TWO_FACTOR_BACKENDS = (
    'id.backends.AllowToBeDisabled', # Disable this to enforce Two Factor Authentication
    'id.backends.TOTPBackend',
    'id.backends.HOTPBackend',
    #'id.backends.YubikeyBackend',
    #'id.backends.OneTimePadBackend',
    #'id.backends.EmailBackend',
)

backends = [getattr(importlib.import_module(mod), cls) for (mod, cls) in (backend.rsplit(".", 1) for backend in TWO_FACTOR_BACKENDS)]

 

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