如何在 Python 中创建同一个类的多个实例并传递不同的参数

Question

I am trying to create a function to create 4 instances of a class Comparer. The class Comparer will compare two csv files with each other. Thus, while creating the instances I need to pass different

I have a class like this:

class Comparer:
    def __init__(
        self
        , file1
        , file2
        , key_column):
    
    self.file1 = file1 
    self.file2 = file2
    self.key_column = key_column 

    # Read in the two files
    file1 = pd.read_csv(self.file1)
    file2 = pd.read_csv(self.file2)

    def compare():
        pass 
     

I would create a single instance like this and pass arguments

comparison1 = Comparer(
    file1 = "xyz/file1.csv",
    file2 = "xyz/file2.csv",
    key_col = 'col1')

comparison1.compare()    

But, I would prefer to create multiple instances in a loop or something which would be efficient. I thought it could be done in the following way.

LIST = [comparison1, comparison2, comparison3, comparison4]

objects = [Comparer() for i in LIST]
for obj in objects:
    other_object.add(obj)   

But, I do not know how to change that to be able to pass different arguments (path to the correct .csv) for the different datasets needed in the comparison.

Has someone an idea?

Answer 1

You could try something like defining comparison_metadata:

comparison_metadata= [
    {
        'file1':'xyz/file1a.csv',
        'file2':'xyz/file2a.csv',
        'key_column':'col1a'
    },
    {
        'file1':'xyz/file1b.csv',
        'file2':'xyz/file2b.csv',
        'key_column':'col1b'
    },
]

and then:

comparers = [Comparer(metadata['file1'], metadata['file2'], metadata['key_column']) for metadata in comparison_metadata]

validation check:

print(comparers[1].file1)
print(comparers[1].file2)
print(comparers[1].key_column)

xyz/file1b.csv
xyz/file2b.csv
col1b

Answer 2

class Comparer:
    def __init__(self, file1, file2, key_column):

        self.file1 = file1 
        self.file2 = file2
        self.key_column = key_column 

        # Read in the two files
        file1 = self.file1
        file2 = self.file2

    def compare(self):
        pass
     

comparer_data = {
    0: ["xyz/file1.csv", "xyz/file2.csv", "key1"],
    1: ["abc/file1.csv", "abc/file2.csv", "key2"]
}

comparers = [Comparer(file1= comparer_data[i][0], file2= comparer_data[i][1], key_column= comparer_data[i][2]) for i in comparer_data]

Answer 3

many_args = [
    ["a/file1.csv", "a/file2.csv", "key2"],
    ["b/file1.csv", "b/file2.csv", "key2"],
    ["c/file1.csv", "c/file2.csv", "key2"],
]

comparers = [Comparer(*args) for args in many_args]