问题: pandas.DataFrame.mean删除列

Question

我正在和Google Colab合作创建一个神经网络。我导入了dataset并创建了dataframe，但是当我使用函数mean时，它会删除最后的列(从列“res_x4trap”中删除)。我做错什么了？

下面是代码：

import numpy as np
import pandas as pd
import tensorflow as tf
from tensorflow import keras
from tensorflow.keras import layers
from tensorflow import feature_column
from matplotlib import pyplot as plt

# Data collection
filepath = '/content/netdataset.csv'  
data = pd.read_csv(filepath, sep=";")
data.set_index('INDEX')

test_df = data.sample(frac=0.2, random_state=1337)
train_df = data.drop(test_df.index)

train_df = train_df.reindex(np.random.permutation(train_df.index)) # shuffle the training set

# Calculate the Z-scores of each column in the training set and
# write those Z-scores into a new pandas DataFrame named train_df_norm.
train_df_mean = train_df.mean()
train_df_std = train_df.std()
train_df_norm = (train_df - train_df_mean)/train_df_std

# Examine some of the values of the normalized training set. Notice that most 
# Z-scores fall between -2 and +2.
train_df_norm.head()

在此之前：

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之后：

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Answer 1

我遇到了同样的问题，结果我的一列是object类型的，因为有问题的条目，所以熊猫在计算平均值时不知道该怎么做，所以就把它删除了。

因此，使用df.dtypes检查列的d类型