创建自定义估算:国家平均估算(Creating a Custom Estimator: State

2019-10-29 12:18发布

我一直试图建立一个非常简单的初始模型预测的罚款养老院可能期望基于其位置支付的金额。

这是我的类定义

#initial model to predict the amount of fines a nursing home might expect to pay based on its location
from sklearn.base import BaseEstimator, RegressorMixin, TransformerMixin

class GroupMeanEstimator(BaseEstimator, RegressorMixin):
    #defines what a group is by using grouper
    #initialises an empty dictionary for group averages
    def __init__(self, grouper):
        self.grouper = grouper
        self.group_averages = {}

    #Any calculation I require for my predict method goes here
    #Specifically, I want to groupby the group grouper is set by
    #I want to then find out what is the mean penalty by each group
    #X is the data containing the groups
    #Y is fine_totals
    #map each state to its mean fine_tot
    def fit(self, X, y):
        #Use self.group_averages to store the average penalty by group
        Xy = X.join(y) #Joining X&y together
        state_mean_series = Xy.groupby(self.grouper)[y.name].mean() #Creating a series of state:mean penalties
        #populating a dictionary with state:mean key:value pairs
        for row in state_mean_series.iteritems():
            self.group_averages[row[0]] = row[1]
        return self

    #The amount of fine an observation is likely to receive is based on his group mean
    #Want to first populate the list with the number of observations
    #For each observation in the list, what is his group and then set the likely fine to his group mean.
    #Return the list
    def predict(self, X):
        dictionary = self.group_averages
        group = self.grouper
        list_of_predictions = [] #initialising a list to store our return values
        for row in X.itertuples(): #iterating through each row in X
            prediction = dictionary[row.STATE] #Getting the value from group_averages dict using key row.group
            list_of_predictions.append(prediction)
        return list_of_predictions

它适用于本 state_model.predict(data.sample(5))

但打破了,当我尝试这样做: state_model.predict(pd.DataFrame([{'STATE': 'AS'}]))

我的模型无法处理的可能性,我想寻求帮助整顿了。

Answer 1:

我看到的问题是在你的fit方法, iteritems在列,而不是行基本上迭代。 你应该使用itertuples这将给你行式数据。 只是改变了循环在你的fit方法

for row in pd.DataFrame(state_mean_series).itertuples(): #row format is [STATE, mean_value]
    self.group_averages[row[0]] = row[1]

然后在您的预测方法,只是做一做故障安全检查

prediction = dictionary.get(row.STATE, None) # None is the default value here in case the 'AS' doesn't exist. you may replace it with what ever you want


文章来源: Creating a Custom Estimator: State Mean Estimator