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+# -*- coding:utf-8 -*-
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+"""
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+@author: yq
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+@time: 2024/1/2
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+@desc: iv值及单调性筛选类
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+"""
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+from itertools import combinations_with_replacement
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+from typing import List, Dict
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+
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+import matplotlib.pyplot as plt
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+import numpy as np
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+import pandas as pd
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+import scorecardpy as sc
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+import seaborn as sns
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+from pandas.core.dtypes.common import is_numeric_dtype
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+
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+from entitys import DataSplitEntity, CandidateFeatureEntity, DataPreparedEntity, DataFeatureEntity, MetricFucEntity
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+from init import f_get_save_path
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+from .feature_utils import f_judge_monto, f_get_corr
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+from .filter_strategy_base import FilterStrategyBase
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+
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+plt.rcParams['figure.figsize'] = (8, 8)
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+
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+
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+class StrategyIv(FilterStrategyBase):
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+
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+ def __init__(self, *args, **kwargs):
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+ super().__init__(*args, **kwargs)
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+
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+ def _f_save_var_trend(self, bins, x_columns_candidate, prefix):
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+ image_path_list = []
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+ for k in x_columns_candidate:
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+ bin_df = bins[k]
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+ # bin_df["bin"] = bin_df["bin"].apply(lambda x: re.sub(r"(\d+\.\d+)",
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+ # lambda m: "{:.2f}".format(float(m.group(0))), x))
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+ sc.woebin_plot(bin_df)
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+ path = f_get_save_path(f"{prefix}_{k}.png")
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+ plt.savefig(path)
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+ image_path_list.append(path)
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+ return image_path_list
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+
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+ def _f_get_bins_by_breaks(self, data: pd.DataFrame, candidate_dict: Dict[str, CandidateFeatureEntity],
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+ y_column=None):
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+ y_column = self.data_process_config.y_column if y_column is None else y_column
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+ special_values = self.data_process_config.special_values
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+ x_columns_candidate = list(candidate_dict.keys())
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+ breaks_list = {}
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+ for column, candidate in candidate_dict.items():
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+ breaks_list[column] = candidate.breaks_list
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+ bins = sc.woebin(data[x_columns_candidate + [y_column]], y=y_column, breaks_list=breaks_list,
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+ special_values=special_values)
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+ return bins
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+
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+ def _f_corr_filter(self, data: DataSplitEntity, candidate_dict: Dict[str, CandidateFeatureEntity]) -> List[str]:
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+ # 相关性剔除变量
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+ corr_threshold = self.data_process_config.corr_threshold
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+ train_data = data.train_data
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+ x_columns_candidate = list(candidate_dict.keys())
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+
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+ bins = self._f_get_bins_by_breaks(train_data, candidate_dict)
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+ train_woe = sc.woebin_ply(train_data[x_columns_candidate], bins)
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+ corr_df = f_get_corr(train_woe)
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+ corr_dict = corr_df.to_dict()
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+ for column, corr in corr_dict.items():
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+ column = column.replace("_woe", "")
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+ if column not in x_columns_candidate:
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+ continue
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+ for challenger_column, challenger_corr in corr.items():
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+ challenger_column = challenger_column.replace("_woe", "")
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+ if challenger_corr < corr_threshold or column == challenger_column \
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+ or challenger_column not in x_columns_candidate:
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+ continue
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+ iv_max = candidate_dict[column].iv_max
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+ challenger_iv_max = candidate_dict[challenger_column].iv_max
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+ if iv_max > challenger_iv_max:
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+ x_columns_candidate.remove(challenger_column)
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+ else:
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+ x_columns_candidate.remove(column)
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+ break
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+ return x_columns_candidate
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+
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+ def _f_wide_filter(self, data: DataSplitEntity) -> Dict:
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+ # 粗筛变量
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+ train_data = data.train_data
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+ test_data = data.test_data
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+ special_values = self.data_process_config.special_values
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+ y_column = self.data_process_config.y_column
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+ iv_threshold_wide = self.data_process_config.iv_threshold_wide
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+ x_columns_candidate = self.data_process_config.x_columns_candidate
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+ if x_columns_candidate is None or len(x_columns_candidate) == 0:
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+ x_columns_candidate = train_data.columns.tolist()
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+ x_columns_candidate.remove(y_column)
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+
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+ bins_train = sc.woebin(train_data[x_columns_candidate + [y_column]], y=y_column, special_values=special_values,
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+ bin_num_limit=5)
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+
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+ breaks_list = {}
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+ for column, bin in bins_train.items():
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+ breaks_list[column] = list(bin['breaks'])
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+ bins_test = None
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+ if test_data is not None and len(test_data) != 0:
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+ bins_test = sc.woebin(test_data[x_columns_candidate + [y_column]], y=y_column, breaks_list=breaks_list,
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+ special_values=special_values
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+ )
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+ bins_iv_dict = {}
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+ for column, bin_train in bins_train.items():
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+ train_iv = bin_train['total_iv'][0]
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+ test_iv = 0
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+ if bins_test is not None:
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+ bin_test = bins_test[column]
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+ test_iv = bin_test['total_iv'][0]
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+ iv_max = train_iv + test_iv
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+ if train_iv < iv_threshold_wide:
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+ continue
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+ bins_iv_dict[column] = {"iv_max": iv_max, "breaks_list": breaks_list[column]}
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+ return bins_iv_dict
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+
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+ def _f_get_best_bins_numeric(self, data: DataSplitEntity, x_column: str):
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+ # 贪婪搜索【训练集】及【测试集】加起来【iv】值最高的且【单调】的分箱
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+ interval = self.data_process_config.bin_search_interval
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+ iv_threshold = self.data_process_config.iv_threshold
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+ special_values = self.data_process_config.get_special_values(x_column)
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+ y_column = self.data_process_config.y_column
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+ sample_rate = self.data_process_config.sample_rate
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+
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+ def _n0(x):
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+ return sum(x == 0)
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+
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+ def _n1(x):
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+ return sum(x == 1)
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+
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+ def _f_distribute_balls(balls, boxes):
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+ # 计算在 balls - 1 个空位中放入 boxes - 1 个隔板的方法数
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+ total_ways = combinations_with_replacement(range(balls + boxes - 1), boxes - 1)
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+ distribute_list = []
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+ # 遍历所有可能的隔板位置
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+ for combo in total_ways:
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+ # 根据隔板位置分配球
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+ distribution = [0] * boxes
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+ start = 0
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+ for i, divider in enumerate(combo):
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+ distribution[i] = divider - start + 1
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+ start = divider + 1
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+ distribution[-1] = balls - start # 最后一个箱子的球数
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+ # 确保每个箱子至少有一个球
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+ if all(x > 0 for x in distribution):
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+ distribute_list.append(distribution)
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+ return distribute_list
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+
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+ def _get_sv_bins(df, x_column, y_column, special_values):
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+ # special_values_bins
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+ sv_bin_list = []
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+ for special in special_values:
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+ dtm = df[df[x_column] == special]
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+ if len(dtm) != 0:
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+ dtm['bin'] = [str(special)] * len(dtm)
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+ binning = dtm.groupby(['bin'], group_keys=False)[y_column].agg(
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+ [_n0, _n1]).reset_index().rename(columns={'_n0': 'good', '_n1': 'bad'})
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+ binning['is_special_values'] = [True] * len(binning)
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+ sv_bin_list.append(binning)
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+ return sv_bin_list
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+
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+ def _get_bins(df, x_column, y_column, breaks_list):
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+ dtm = pd.DataFrame({'y': df[y_column], 'value': df[x_column]})
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+ bstbrks = [-np.inf] + breaks_list + [np.inf]
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+ labels = ['[{},{})'.format(bstbrks[i], bstbrks[i + 1]) for i in range(len(bstbrks) - 1)]
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+ dtm.loc[:, 'bin'] = pd.cut(dtm['value'], bstbrks, right=False, labels=labels)
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+ dtm['bin'] = dtm['bin'].astype(str)
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+ bins = dtm.groupby(['bin'], group_keys=False)['y'].agg([_n0, _n1]) \
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+ .reset_index().rename(columns={'_n0': 'good', '_n1': 'bad'})
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+ bins['is_special_values'] = [False] * len(bins)
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+ return bins
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+
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+ def _calculation_iv(bins):
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+ bins['count'] = bins['good'] + bins['bad']
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+ bins['badprob'] = bins['bad'] / bins['count']
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+ # 单调性判断
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+ bad_prob = bins[bins['is_special_values'] == False]['badprob'].values.tolist()
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+ if not f_judge_monto(bad_prob):
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+ return -1
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+ # 计算iv
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+ infovalue = pd.DataFrame({'good': bins['good'], 'bad': bins['bad']}) \
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+ .replace(0, 0.9) \
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+ .assign(
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+ DistrBad=lambda x: x.bad / sum(x.bad),
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+ DistrGood=lambda x: x.good / sum(x.good)
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+ ) \
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+ .assign(iv=lambda x: (x.DistrBad - x.DistrGood) * np.log(x.DistrBad / x.DistrGood)) \
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+ .iv
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+ bins['bin_iv'] = infovalue
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+ bins['total_iv'] = bins['bin_iv'].sum()
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+ iv = bins['total_iv'].values[0]
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+ return iv
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+
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+ def _f_sampling(distribute_list: list, sample_rate: float):
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+ # 采样,完全贪婪搜索耗时太长
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+ sampled_list = distribute_list[::int(1 / sample_rate)]
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+ return sampled_list
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+
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+ train_data = data.train_data
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+ train_data_filter = train_data[~train_data[x_column].isin(special_values)]
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+ train_data_filter = train_data_filter.sort_values(by=x_column, ascending=True)
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+ train_data_x = train_data_filter[x_column]
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+
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+ test_data = data.test_data
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+ test_data_filter = None
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+ if test_data is not None and len(test_data) != 0:
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+ test_data_filter = test_data[~test_data[x_column].isin(special_values)]
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+ test_data_filter = test_data_filter.sort_values(by=x_column, ascending=True)
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+
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+ # 构造数据切分点
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+ # 计算 2 - 5 箱的情况
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+ distribute_list = []
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+ points_list = []
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+ for bin_num in list(range(2, 6)):
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+ distribute_list_cache = _f_distribute_balls(int(1 / interval), bin_num)
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+ # 4箱及以上得采样,不然耗时太久
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+ sample_num = 1000 * sample_rate
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+ if sample_rate <= 0.15:
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+ sample_num *= 2
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+ if bin_num == 4 and len(distribute_list_cache) >= sample_num:
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+ distribute_list_cache = _f_sampling(distribute_list_cache, sample_num / len(distribute_list_cache))
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+ sample_num = 4000 * sample_rate
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+ if bin_num == 5 and len(distribute_list_cache) >= sample_num:
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+ distribute_list_cache = _f_sampling(distribute_list_cache, sample_num / len(distribute_list_cache))
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+ distribute_list.extend(distribute_list_cache)
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+ for distribute in distribute_list:
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+ point_list_cache = []
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+ point_percentile_list = [sum(distribute[0:idx + 1]) * interval for idx, _ in enumerate(distribute[0:-1])]
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+ for point_percentile in point_percentile_list:
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+ point = train_data_x.iloc[int(len(train_data_x) * point_percentile)]
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+ if point not in point_list_cache:
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+ point_list_cache.append(point)
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+ if point_list_cache not in points_list:
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+ points_list.append(point_list_cache)
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+ # IV与单调性过滤
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+ iv_max = 0
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+ breaks_list = []
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+ train_sv_bin_list = _get_sv_bins(train_data, x_column, y_column, special_values)
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+ test_sv_bin_list = None
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+ if test_data_filter is not None:
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+ test_sv_bin_list = _get_sv_bins(test_data, x_column, y_column, special_values)
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+ from tqdm import tqdm
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+ for point_list in tqdm(points_list):
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+ train_bins = _get_bins(train_data_filter, x_column, y_column, point_list)
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+ # 与special_values合并计算iv
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+ for sv_bin in train_sv_bin_list:
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+ train_bins = pd.concat((train_bins, sv_bin))
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+ train_iv = _calculation_iv(train_bins)
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+ # 只限制训练集的单调性与iv值大小
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+ if train_iv < iv_threshold:
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+ continue
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+
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+ test_iv = 0
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+ if test_data_filter is not None:
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+ test_bins = _get_bins(test_data_filter, x_column, y_column, point_list)
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+ for sv_bin in test_sv_bin_list:
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+ test_bins = pd.concat((test_bins, sv_bin))
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+ test_iv = _calculation_iv(test_bins)
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+ iv = train_iv + test_iv
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+ if iv > iv_max:
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+ iv_max = iv
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+ breaks_list = point_list
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+
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+ return iv_max, breaks_list
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+
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+ def filter(self, data: DataSplitEntity, *args, **kwargs) -> Dict[str, CandidateFeatureEntity]:
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+ # 粗筛
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+ bins_iv_dict = self._f_wide_filter(data)
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+ x_columns_candidate = list(bins_iv_dict.keys())
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+ candidate_num = self.data_process_config.candidate_num
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+ candidate_dict: Dict[str, CandidateFeatureEntity] = {}
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+ for x_column in x_columns_candidate:
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+ if is_numeric_dtype(data.train_data[x_column]):
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+ iv_max, breaks_list = self._f_get_best_bins_numeric(data, x_column)
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+ candidate_dict[x_column] = CandidateFeatureEntity(x_column, breaks_list, iv_max)
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+ else:
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+ # 字符型暂时用scorecardpy来处理
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+ candidate_dict[x_column] = CandidateFeatureEntity(x_column, bins_iv_dict[x_column]["breaks_list"],
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+ bins_iv_dict[x_column]["iv_max"])
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+
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+ # 相关性进一步剔除变量
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+ x_columns_candidate = self._f_corr_filter(data, candidate_dict)
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+ candidate_list: List[CandidateFeatureEntity] = []
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+ for x_column, v in candidate_dict.items():
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+ if x_column in x_columns_candidate:
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+ candidate_list.append(v)
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+
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+ candidate_list.sort(key=lambda x: x.iv_max, reverse=True)
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+ candidate_list = candidate_list[0:candidate_num]
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+ candidate_dict = {}
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+ for candidate in candidate_list:
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+ candidate_dict[candidate.x_column] = candidate
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+ return candidate_dict
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+
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+ def feature_generate(self, data: DataSplitEntity, candidate_dict: Dict[str, CandidateFeatureEntity], *args,
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+ **kwargs) -> DataPreparedEntity:
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+ train_data = data.train_data
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+ val_data = data.val_data
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+ test_data = data.test_data
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+ y_column = self.data_process_config.y_column
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+ x_columns_candidate = list(candidate_dict.keys())
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+ bins = self._f_get_bins_by_breaks(train_data, candidate_dict)
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+
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+ train_woe = sc.woebin_ply(train_data[x_columns_candidate], bins)
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+ train_data_feature = DataFeatureEntity(pd.concat((train_woe, train_data[y_column]), axis=1),
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+ train_woe.columns.tolist(), y_column)
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+
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+ val_data_feature = None
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+ if val_data is not None and len(val_data) != 0:
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+ val_woe = sc.woebin_ply(val_data[x_columns_candidate], bins)
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+ val_data_feature = DataFeatureEntity(pd.concat((val_woe, val_data[y_column]), axis=1),
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+ train_woe.columns.tolist(), y_column)
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+
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+ test_data_feature = None
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+ if test_data is not None and len(test_data) != 0:
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+ test_woe = sc.woebin_ply(test_data[x_columns_candidate], bins)
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+ test_data_feature = DataFeatureEntity(pd.concat((test_woe, test_data[y_column]), axis=1),
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+ train_woe.columns.tolist(), y_column)
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+ return DataPreparedEntity(train_data_feature, val_data_feature, test_data_feature)
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+
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+ def feature_report(self, data: DataSplitEntity, candidate_dict: Dict[str, CandidateFeatureEntity], *args,
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+ **kwargs) -> Dict[str, MetricFucEntity]:
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+ y_column = self.data_process_config.y_column
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+ x_columns_candidate = list(candidate_dict.keys())
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+ train_data = data.train_data
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+ test_data = data.test_data
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+
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+ metric_value_dict = {}
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+ # 样本分布
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+ metric_value_dict["样本分布"] = MetricFucEntity(table=data.get_distribution(y_column), table_font_size=12,
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+ table_cell_width=3)
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+ # 变量iv及psi
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+ train_bins = self._f_get_bins_by_breaks(train_data, candidate_dict)
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+ train_iv = {key_: [round(value_['total_iv'].max(), 4)] for key_, value_ in train_bins.items()}
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+ train_iv = pd.DataFrame.from_dict(train_iv, orient='index', columns=['IV']).reset_index()
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+ train_iv = train_iv.sort_values('IV', ascending=False).reset_index(drop=True)
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+ train_iv.columns = ['变量', 'IV']
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+
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+ if test_data is not None and len(test_data) != 0:
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+ # 计算psi仅需把y改成识别各自训练集测试集即可
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+ psi_df = pd.concat((train_data, test_data))
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+ psi_df["#target#"] = [1] * len(train_data) + [0] * len(test_data)
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+ psi = self._f_get_bins_by_breaks(psi_df, candidate_dict, y_column="#target#")
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+ psi = {key_: [round(value_['total_iv'].max(), 4)] for key_, value_ in psi.items()}
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+ psi = pd.DataFrame.from_dict(psi, orient='index', columns=['psi']).reset_index()
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+ psi.columns = ['变量', 'psi']
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+ train_iv = pd.merge(train_iv, psi, on="变量", how="left")
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+
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+ # 变量趋势-测试集
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+ test_bins = self._f_get_bins_by_breaks(test_data, candidate_dict)
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+ image_path_list = self._f_save_var_trend(test_bins, x_columns_candidate, "test")
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+ metric_value_dict["变量趋势-测试集"] = MetricFucEntity(image_path=image_path_list, image_size=4)
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+
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+ metric_value_dict["变量iv"] = MetricFucEntity(table=train_iv, table_font_size=12, table_cell_width=3)
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+ # 变量趋势-训练集
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+ image_path_list = self._f_save_var_trend(train_bins, x_columns_candidate, "train")
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+ metric_value_dict["变量趋势-训练集"] = MetricFucEntity(image_path=image_path_list, image_size=4)
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+ # 变量有效性
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+ train_woe = sc.woebin_ply(train_data[x_columns_candidate], train_bins)
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+ train_corr = f_get_corr(train_woe)
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+ plt.figure(figsize=(12, 12))
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+ sns.heatmap(train_corr, vmax=1, square=True, cmap='RdBu', annot=True)
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+ plt.title('Variables Correlation', fontsize=15)
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+ plt.yticks(rotation=0)
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+ plt.xticks(rotation=90)
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+ path = f_get_save_path(f"var_corr.png")
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+ plt.savefig(path)
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+ metric_value_dict["变量有效性"] = MetricFucEntity(image_path=path)
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+
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+ return metric_value_dict
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