median_target('BMI') data.loc[(data['Outcome'] == 0 ) & (data['BMI'].isnull()), 'BMI'] = 30.1 data.loc[(data['Outcome'] == 1 ) & (data['BMI'].isnull()), 'BMI'] = 34.3

这段代码的作用是根据'BMI'特征的中位数填充该特征的缺失值。具体来说，先定义了一个函数`median_target()`，该函数的参数是特征名，函数的作用是返回该特征按照目标变量（'Outcome'）分组后各组的中位数。然后在代码中，分别对目标变量为0和1的样本中'BMI'特征的缺失值进行填充，填充的值分别为30.1和34.3，这两个值分别是目标变量为0和1的样本中'BMI'特征的中位数。通过这种方法，可以利用目标变量的信息来填充缺失值，以提高数据的完整性和准确性。

相关问题

解析 def explore_city_data(self,city_data): housing_prices = city_data.target housing_features = city_data.data num_houses = np.shape(city_data.data) num_features = np.shape(city_data.data) min_price = np.min(city_data.target) max_price = np.max(city_data.target) mean_price = np.mean(city_data.target) median_price = np.median(city_data.target) stand_dev = np.std(city_data.target)

这段代码定义了一个名为"explore_city_data"的函数，该函数有一个参数"city_data"。该函数的主要目的是从给定的城市数据中提取一些基本信息，包括房屋价格、特征数量、房屋数量、最小价格、最大价格、平均价格、中位价格和标准差。

具体来说，该函数将从给定的城市数据中提取房屋价格和特征，并计算出特征数量和房屋数量。然后，该函数将使用NumPy库中的函数来计算出最小价格、最大价格、平均价格、中位价格和标准差，这些计算都是基于房屋价格数据。

最后的结果将作为函数的返回值，因此，该函数将返回一个元组，其中包含所有的计算结果。

function median_target(var) { temp = data[data[var].notnull()]; temp = temp[[var, 'Outcome']].groupby(['Outcome'])[[var]].median().reset_index(); return temp; } data.loc[(data['Outcome'] == 0) & (data['Insulin'].isnull()), 'Insulin'] = 102.5; data.loc[(data['Outcome'] == 1) & (data['Insulin'].isnull()), 'Insulin'] = 169.5; data.loc[(data['Outcome'] == 0) & (data['Glucose'].isnull()), 'Glucose'] = 107; data.loc[(data['Outcome'] == 1) & (data['Glucose'].isnull()), 'Glucose'] = 1; data.loc[(data['Outcome'] == 0) & (data['SkinThickness'].isnull()), 'SkinThickness'] = 27; data.loc[(data['Outcome'] == 1) & (data['SkinThickness'].isnull()), 'SkinThickness'] = 32; data.loc[(data['Outcome'] == 0) & (data['BloodPressure'].isnull()), 'BloodPressure'] = 70; data.loc[(data['Outcome'] == 1) & (data['BloodPressure'].isnull()), 'BloodPressure'] = 74.5; data.loc[(data['Outcome'] == 0) & (data['BMI'].isnull()), 'BMI'] = 30.1; data.loc[(data['Outcome'] == 1) & (data['BMI'].isnull()), 'BMI'] = 34.3; target_col = ["Outcome"]; cat_cols = data.nunique()[data.nunique() < 12].keys().tolist(); cat_cols = [x for x in cat_cols]; num_cols = [x for x in data.columns if x not in cat_cols + target_col]; bin_cols = data.nunique()[data.nunique() == 2].keys().tolist(); multi_cols = [i for i in cat_cols if i in bin_cols]; le = LabelEncoder(); for i in bin_cols: data[i] = le.fit_transform(data[i]); data = pd.get_dummies(data=data, columns=multi_cols); std = StandardScaler(); scaled = std.fit_transform(data[num_cols]); scaled = pd.DataFrame(scaled, columns=num_cols); df_data_og = data.copy(); data = data.drop(columns=num_cols, axis=1); data = data.merge(scaled, left_index=True, right_index=True, how='left'); X = data.drop('Outcome', axis=1); y = data['Outcome']; X_train, X_test, y_train, y_test = train_test_split(X, y, train_size=0.8, shuffle=True, random_state=1); y_train = to_categorical(y_train); y_test = to_categorical(y_test);将这段代码添加注释

# 导入必要的库
import pandas as pd
from sklearn.preprocessing import LabelEncoder, StandardScaler
from keras.utils import to_categorical
from sklearn.model_selection import train_test_split

# 定义函数，返回每个特征在不同结果下的中位数
def median_target(var):
temp = data[data[var].notnull()]
temp = temp[[var, 'Outcome']].groupby(['Outcome'])[[var]].median().reset_index()
return temp

# 将缺失值填充为中位数
data.loc[(data['Outcome'] == 0) & (data['Insulin'].isnull()), 'Insulin'] = 102.5
data.loc[(data['Outcome'] == 1) & (data['Insulin'].isnull()), 'Insulin'] = 169.5
data.loc[(data['Outcome'] == 0) & (data['Glucose'].isnull()), 'Glucose'] = 107
data.loc[(data['Outcome'] == 1) & (data['Glucose'].isnull()), 'Glucose'] = 1
data.loc[(data['Outcome'] == 0) & (data['SkinThickness'].isnull()), 'SkinThickness'] = 27
data.loc[(data['Outcome'] == 1) & (data['SkinThickness'].isnull()), 'SkinThickness'] = 32
data.loc[(data['Outcome'] == 0) & (data['BloodPressure'].isnull()), 'BloodPressure'] = 70
data.loc[(data['Outcome'] == 1) & (data['BloodPressure'].isnull()), 'BloodPressure'] = 74.5
data.loc[(data['Outcome'] == 0) & (data['BMI'].isnull()), 'BMI'] = 30.1
data.loc[(data['Outcome'] == 1) & (data['BMI'].isnull()), 'BMI'] = 34.3

# 将数据进行分类处理
target_col = ["Outcome"]
cat_cols = data.nunique()[data.nunique() < 12].keys().tolist()
cat_cols = [x for x in cat_cols]
num_cols = [x for x in data.columns if x not in cat_cols + target_col]
bin_cols = data.nunique()[data.nunique() == 2].keys().tolist()
multi_cols = [i for i in cat_cols if i in bin_cols]

# 对二分类特征进行编码
le = LabelEncoder()
for i in bin_cols:
data[i] = le.fit_transform(data[i])

# 将分类特征进行独热编码
data = pd.get_dummies(data=data, columns=multi_cols)

# 对数值特征进行标准化
std = StandardScaler()
scaled = std.fit_transform(data[num_cols])
scaled = pd.DataFrame(scaled, columns=num_cols)

# 将数据进行合并
df_data_og = data.copy()
data = data.drop(columns=num_cols, axis=1)
data = data.merge(scaled, left_index=True, right_index=True, how='left')

# 划分训练集和测试集，对标签进行独热编码
X = data.drop('Outcome', axis=1)
y = data['Outcome']
X_train, X_test, y_train, y_test = train_test_split(X, y, train_size=0.8, shuffle=True, random_state=1)
y_train = to_categorical(y_train)
y_test = to_categorical(y_test)