lgb模型测试集标签报错


from sklearn.datasets import load_iris
from sklearn.metrics import accuracy_score, precision_score
from sklearn.model_selection import train_test_split
from sklearn.tree import DecisionTreeClassifier
from sklearn.preprocessing import LabelEncoder
import pandas as pd
import numpy as np
import re
import gc
import pdb

new_data = pd.read_csv(r'C:\Users\86188\PycharmProjects\pythonProject8\src\data4.csv')
# 将所有缺失值替换为0
new_data.fillna(0, inplace=True)
gc.collect()
# 删除 event_type 列
new_data = new_data.drop('event_type', axis=1)
X = new_data.drop(["user_id","product_id","new_column"], axis=1)
y = new_data["new_column"]
# 将数据集划分为训练集和测试集
X_train, X_test, y_train, y_test = train_test_split(X, y, test_size=0.2, random_state=42,stratify=X)

le = LabelEncoder()
y_train = le.fit_transform(y_train)
'''le = LabelEncoder().fit(y_train+y_test)
y_train = le.transform(y_train)
y_test = le.transform(y_test)'''
'''y_test=y_test.map(lambda s:'<unknown>'if s not in y_train else s)
y_train=np.y_trainend(y_train,'<unknown.
#y_test = y_test.drop(index=83394)'''
# 检查索引值是否存在
'''if 83394 in y_test.index:
    y_test = y_test.drop(index=83394)
else:
    print("Index 83394 not found in series.")'''
import lightgbm as lgb
from lightgbm import LGBMClassifier
from sklearn.metrics import accuracy_score
from sklearn.model_selection import cross_val_score
from sklearn.model_selection import GridSearchCV

# 定义xgboost模型
lgb_model = lgb.LGBMClassifier()

# 设置参数空间
params = {
          'boosting_type': 'gbdt',
          'objective': 'multiclass',
          'metric': 'multi_log_loss',
          'min_child_weight': 1.5,
          'num_leaves': 2**5,
          'lambda_l2': 10,
          'subsample': 0.7,
          'learning_rate': 0.03,
          'seed': 2017,
          "num_class": 2,
          'silent': True,
          }

# 输出最优参数

print('Best Parameter:', params)

# 使用最优参数构建新的xgboost模型
lgb_model = lgb.LGBMClassifier(**params)

# 使用训练集对新模型进行拟合
# X_train = np.array(X_train)
# pdb.set_trace()
lgb_model.fit(X_train, y_train)

# 使用新模型进行预测
y_pred = lgb_model.predict(X_test)

ValueError: The least populated class in y has only 1 member, which is too few. The minimum number of groups for any class cannot be less than 2.应该怎么解决,有没有大佬帮帮忙

这段代码存在一些问题:

from sklearn.datasets import load_iris 语句后面缺少了 import语句的结束括号,应该为 from sklearn.datasets import load_iris;
import pandas as pd 语句后面缺少了分号,应该为 import pandas as pd;
import numpy as np 语句后面缺少了分号,应该为 import numpy as np;
import re 语句后面缺少了分号,应该为 import re;
pdb 是Python的调试器(Debugger),通常在调试代码时使用,不应该在生产代码中启用。可以考虑注释掉相关代码或者使用其他调试工具。
new_data.fillna(0, inplace=True) 将所有缺失值替换为0,可能会导致特征值的分布不均衡,从而影响分类效果。可以考虑使用其他方法来处理缺失值。
X = new_data.drop(["user_id","product_id","new_column"], axis=1) 删除了事件类型列和其他三个特征列,只剩下用户ID、产品ID和目标列,这样的操作可能导致数据集失去了很多有价值的信息,分类效果可能会受到影响。
X_train, X_test, y_train, y_test = train_test_split(X, y, test_size=0.2, random_state=42,stratify=X) 使用了train_test_split函数将数据集划分为训练集和测试集,但是 stratify参数设置为X,不太合理,应该设置为y。
le = LabelEncoder().fit(y_train+y_test) 使用了LabelEncoder将目标列编码为数字,但是这里只对训练集进行了编码,可能会导致测试集的目标列无法被正确解码。建议分别对训练集和测试集的目标列进行编码。