import numpy as np a = np.array([1.0, np.nan, 3.0]) a = np.nan_to_num(a, nan=-1) # 将 NaN 转换成 -1 a = a.astype(int) # 将浮点数转换成整数 print(a)这里面的1或者3代表什么

这里的1和3代表数组中的元素值，它们分别表示原始数组中的1.0和3.0，经过转换后变成了整数。在这段代码中，使用了numpy库中的nan_to_num函数，将原始数组中的NaN值替换成了-1，然后使用astype函数将浮点数转换成整数。最终输出的数组中，原来的1.0变成了1，原来的3.0变成了3，而原来的NaN值则变成了-1。

相关问题

import random import pandas as pd import numpy as np import matplotlib.pyplot as plt from sklearn.cluster import KMeans from sklearn.metrics import silhouette_score from sklearn.decomposition import PCA plt.rcParams['font.sans-serif'] = ['SimHei'] dataset=pd.read_excel('C:\\Users\\86180\\Desktop\\第一次数学建模\\湘菜口感好物质.xlsx') dataset = dataset.drop(dataset.index[:1], inplace=False) dataset = dataset.drop(dataset.columns[:1], axis=1, inplace=False) #matrix=dataset.values matrix=np.array(dataset) matrix=matrix.T matrix_xiang=matrix[:27] # 将NaN值替换为0 matrix_xiang = np.nan_to_num(matrix_xiang) # 检测矩阵中是否还有NaN值 这个代码报错TypeError: ufunc 'isnan' not supported for the input types, and the inputs could not be safely coerced to any supported types according to the casting rule ''safe''应如何修改

根据您提供的代码，错误出在尝试检测矩阵中是否还有NaN值时。出现错误的原因可能是矩阵中的元素类型不符合`np.isnan()`函数的要求。

为了解决这个问题，您可以尝试使用`np.isnan()`函数之前，先将矩阵的元素类型转换为浮点类型（float），然后再进行检测。下面是修改后的代码：

import random
import pandas as pd
import numpy as np
import matplotlib.pyplot as plt
from sklearn.cluster import KMeans
from sklearn.metrics import silhouette_score
from sklearn.decomposition import PCA

plt.rcParams['font.sans-serif'] = ['SimHei']

dataset = pd.read_excel('C:\\Users\\86180\\Desktop\\第一次数学建模\\湘菜口感好物质.xlsx')

dataset = dataset.drop(dataset.index[:1], inplace=False)
dataset = dataset.drop(dataset.columns[:1], axis=1, inplace=False)

matrix = np.array(dataset)
matrix = matrix.T

matrix_xiang = matrix[:27]

# 将NaN值替换为0
matrix_xiang = np.nan_to_num(matrix_xiang.astype(float))

# 检测矩阵中是否还有NaN值
has_nan = np.isnan(matrix_xiang).any()

if has_nan:
    print("矩阵中存在NaN值")
else:
    print("矩阵中没有NaN值")

在上述代码中，我使用`astype(float)`将矩阵的元素类型转换为浮点类型。然后，再对`matrix_xiang`进行NaN值的替换和检测。这样应该能够解决您遇到的问题。

import numpy as np import pandas as pd import matplotlib.pyplot as plt from decision_tree_classifier import DecisionTreeClassifier from random_forest_classifier import RandomForestClassifier from sklearn.model_selection import train_test_split from sklearn.metrics import accuracy_score #读取数据 df = pd.read_csv('adult.csv',encoding='gbk') df.head() col_names=['age','workclass','fnlwgt','education','educational-num','marital-status','occupation','relationship','race','gender','capital-gain','capital-loss','hours-per-week','native-country','income'] df.columns = col_names categorical = ['workclass','education','marital-status','occupation','relationship','race','gender','native-country','income'] # print(f'分类特征：\n{categorical}') # for var in categorical: # print(df[var].value_counts()) #缺失值处理 df['occupation'].replace('?', np.NaN, inplace=True) df['workclass'].replace('?', np.NaN, inplace=True) df['native-country'].replace('?', np.NaN, inplace=True) df.isnull().sum() df['income'].value_counts() plt.rcParams['font.sans-serif'] = ['Microsoft YaHei'] df.isnull().sum() df['workclass'].fillna(df['workclass'].mode()[0], inplace=True) df['occupation'].fillna(df['occupation'].mode()[0], inplace=True) df['native-country'].fillna(df['native-country'].mode()[0], inplace=True) df = pd.get_dummies(df,columns=categorical,drop_first=True) print(df.head()) y = df.loc[:,'income_>50K'] X = np.array(df.loc[:,['age', 'educational-num', 'hours-per-week']]) y = np.array(y) x = np.array(X) y = y.reshape(-1,1) X_train,X_test,y_train,y_test = train_test_split(X,y,test_size=0.2,random_state=1234) from sklearn.ensemble import RandomForestClassifier rtree = RandomForestClassifier(n_estimators=100,max_depth=5,max_features=0.2,max_samples=50,random_state=1234) X_train = np.array(X_train) rtree.fit(X_train, y_train) X_test = np.array(X_test) y_pred = rtree.predict(X_test) accuracy = accuracy_score(y_test,y_pred) print("accuracy={}".format((accuracy)))我这个代码如何更换特征向量

如果想更换特征向量，只需要修改以下代码段：

X = np.array(df.loc[:,['age', 'educational-num', 'hours-per-week']])
y = np.array(y)

将 `['age', 'educational-num', 'hours-per-week']` 替换为你想要的特征向量即可。注意要保证特征向量的格式正确，即为一个列表形式。另外，如果更换特征向量后发现模型表现不佳，可以再考虑增加或减少特征，或者对特征进行预处理等操作。