我使用了sklearn标准分析器(平均去除和方差缩放)来缩放数据帧并将其与数据帧进行比较,其中我"手动"减去平均值并除以标准偏差.比较显示了一致的微小差异.谁能解释为什么？(我使用的数据集是:http://archive.ics.uci.edu/ml/datasets/Wine
import pandas as pd
from sklearn.preprocessing import StandardScaler
df = pd.read_csv("~/DataSets/WineDataSetItaly/wine.data.txt", names=["Class", "Alcohol", "Malic acid", "Ash", "Alcalinity of ash", "Magnesium", "Total phenols", "Flavanoids", "Nonflavanoid phenols", "Proanthocyanins", "Color intensity", "Hue", "OD280/OD315 of diluted wines", "Proline"])
cols = list(df.columns)[1:] # I didn't want to scale the "Class" column
std_scal = StandardScaler()
standardized = std_scal.fit_transform(df[cols])
df_standardized_fit = pd.DataFrame(standardized, index=df.index, columns=df.columns[1:])
df_standardized_manual = (df - df.mean()) / df.std()
df_standardized_manual.drop("Class", axis=1, inplace=True)
df_differences = df_standardized_fit - df_standardized_manual
df_differences.iloc[:,:5]
Alcohol Malic acid …