Instantiate an object using a string as its name in Python

Question

As it stands, I'm reading lines from a file to create "Monster" objects with certain int and string variables for each object. Every 2 lines creates a single object: one for strings, one for integers. Example file:

Slime,Slime ball
4,0,2,1,5,6,1
Pig,Pig skin
6,1,3,2,6,4,1

Here's my code to read from the file:

def read_from_file(file_name):
file = open(file_name)
monster_list = []
line_type = 1 #1=Monster Name, 2=Monster values
for each_line in file:
    if line_type == 1:
        #initialize the monster name
        value_list = each_line.split(",")
        name, trophy = value_list #name = first element, trophy = 2nd element
        line_type = 2
    else:
        if line_type == 2:
            #read values for monster values
            value_list = each_line.split(",") #now ['4','5',...]
            value_list = [int(e) for e in value_list] #now [1,2,3...]
            hp,shield,ap,mod,exp,gold,trophy_count = value_list
            line_type = 1
        monster_list.append(Monster(name, hp, shield, ap, mod, exp, gold, trophy, trophy_count))
#monster(monster_name)
file.close() #Close the file
return monster_list

Is there a way to alter the monster_list.append(...) line to use the name variable to instantiate a Monster object of the name? I.e.,

name = Monster(name, hp, shield, ap, mod, exp, gold, trophy, trophy_count)
monster_list.append(name)

Is this possible, or is there a similar way to accomplish this?

Gargamel · Accepted Answer · 2014-10-24 04:43:04Z

1

As far as I know, there is no way to do this. The reason being (again as far as I know) that there is no practical use for this.

Might I inquire what you would like to accomplish by doing this? Even if it would be possible, I have a feeling there are easier ways to get the result you are trying to achieve...

EDIT:

From your comment I would say you should be using a dictionary instead of a list. This would allow you to do the following:

monster_dict[name] = Monster(name, hp, shield, ap, mod, exp, gold, trophy, trophy_count))

Subsequently, in the function that calls 'read_from_file', you will be able to retrieve each monster by it's name from the dict:

slime = monster_dict['Slime']

edited Oct 24, 2014 at 4:43

answered Oct 24, 2014 at 4:29

Gargamel

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7 Comments

Hawkins Over a year ago

I'm all for an easier way. The idea here is to return a list, monster_list, full of Monster objects. At the moment, I have to access these monster objects by using monster_list[0] etc in the function that calls read_from_file(). I would like to be able to instantiate these as Slime = monster_list[0] but use the name, i.e, monster_list[0].name = monster_list[0].

Gargamel Over a year ago

I edited my answer. Would this work for what you are trying to do?

Hawkins Over a year ago

Possibly... I don't fully understand dictionaries, but if I call monster_dict['Pig'] - what happens? Does that find 'Pig' in the dictionary and finds the reference is an appropriate Monster object? EDIT: Oh, I think I see actually. But how do I return multiple dictionaries? monster_dict['Slime'] and monster_dict['Pig'] ?

Gargamel Over a year ago

Yes, thats basically what happens. You can read more about dictionaries here: docs.python.org/2/tutorial/datastructures.html#dictionaries I would definitely suggest reading about and understanding dictionaries, as they are one of the most fundamental and useful data structures python has to offer! :)

Hawkins Over a year ago

Thank you, that should work! Dictionaries also look rather helpful. It's about time I actually learn to use them! Thanks again.

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