Question

I’m making a combat helper for D&D. I plan to make it get the stats of each monster from a .txt file in this format:

_Name of monster_
HP = 45
AC = 19
Fort = -3

I’m using a class called Monster, and __init__ iterates through the .txt file. It iterates fine, my problem is that I can’t get the variables to have self. before it. Monsterfind() simply finds the path to the monster .txt file, and I know that is not the problem, as the variables are printing fine.

class Monster:
    def __init__(self, monster):
        """Checks if the monster is defined in the directory. 
        If it is, sets class attributes to be the monster's as decided in its .txt file"""
        self.name = monster.capitalize()
        monstercheck = self.monsterfind()
        if monstercheck != Fales:
            monsterchck = open(monstercheck, 'r')
            print monstercheck.next() # Print the _Name of Monsters, so it does not execute
            for stat in monstercheck:
                print 'self.{}'.format(stat) # This is to check it has the correct .txt file
                eval('self.{}'.format(stat))
            monstercheck.close()
            print 'Monster loaded'
        else: # if unfound
            print '{} not found, add it?'.format(self.name)
            if raw_input('Y/N\n').capitalize() == 'Y':
                self.addmonster() # Function that just makes a new file
            else:
                self.name = 'UNKNOWN'

It just says: self.AC = 5 SyntaxError: invalid syntax @ the equals sign

If there is any problem with my class or my __init__, even if it is unimportant, please tell me as this is the first time I’m using classes.

Thank you in advance

Answer 1

You don’t need eval() (or exec) here (they should pretty much never be used) – Python has setattr(), which does what you want.

Note that it might be easier to use a data format that already exists, such as JSON, to avoid manually parsing it.

As another note, when working with files, it’s best to use a context manager, as it reads nicely, and ensures a file is closed, even if there is an exception:

with open(monstercheck, 'r') as monsterchck:
        print monstercheck.next()
        for stat, value in parse(monstercheck):
            setattr(self, stat, value)

Obviously, you would need to do some real parsing here.