[FIXED] can someone explain me this python pipeline syntax

Issue

1. I am a bit confused about what exactly every function within this pipeline does. Can someone explain how this pipeline works? I know roughly how, but some clarification would be immensely helpful.

2. Why is capital 'X' used in def transform(self, X)?

3. What's the point of get_feature_names and __init__ specifically?

Code:

class custom_fico(BaseEstimator,TransformerMixin):
    
        def __init__(self):
            self.feature_names = ['fico']
    
        def fit(self,x,y=None):
            return self
    
        def transform(self,X):
            k = X['FICO.Range'].str.split('-',expand = True).astype(float)
            fico = 0.5 * (k[0] + k[1])
            return pd.DataFrame({'fico':fico})
    
        def get_feature_names(self):
            return self.feature_names

Solution

1- try this link. Very helpful to understand everything and it makes everything clear. https://medium.com/@shivangisareen/pipelining-in-python-7edd2382f67d

2- I think that its not necessary to use capital X. I think you can use anything else and still work but in this case the code writer just chose capital x.

3- and lastly, the init method is similar to constructors in C++ and Java . Constructors are used to initialize the object's state. The task of constructors is to initialize(assign values) to the data members of the class when an object of class is created.

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Answered By - Ahmed Hamouda