arr = np.asarray(values, dtype=dtype) ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ ValueError: could not convert string to float: ' b'
时间: 2023-08-02 14:08:20 浏览: 90
这个错误提示是因为在将数据转换为numpy数组时,存在字符串类型的特征,而numpy数组只接受数值类型的特征。因此,需要将字符串类型的特征进行编码,将其转换为数值类型的特征。
一种常见的方法是使用 `LabelEncoder` 对字符串类型的特征进行编码。具体方法如下:
```python
from sklearn.preprocessing import LabelEncoder
# 加载数据集
df = pd.read_csv('breast_cancer.csv')
# 对字符串类型的特征进行编码
le = LabelEncoder()
df['feature_name'] = le.fit_transform(df['feature_name'])
# 将DataFrame转换为numpy数组
arr = df.to_numpy()
```
其中,`feature_name` 是需要进行编码的特征名称。上面的代码中使用 `LabelEncoder` 对 `feature_name` 进行编码,并将编码后的结果替换原来的特征。最后,使用 `to_numpy()` 方法将DataFrame转换为numpy数组,从而消除了上述错误提示。
相关问题
错误改正:import xlrd import numpy as np wb=xlrd.open("历年总人口.xls") sheet=wb.sheet_by_index(0) col_0=sheet.col_values(0) col_1=sheet.col_values(1) col_2=sheet.col_values(2) col_4=sheet.col_values(4) year=col_0[38:] total=col_1[38:] man=col_2[38:] woman=col_4[38:] year=[int(c) for c in year] total=[int(c) for c in total] man=[int(c) for c in man] woman=[int(c) for c in woman] arr=np.array(year).reshape(m,1) arr=np.insert(arr,1,values=total,axis=1) arr=np.insert(arr,1,values=man,axis=1) arr=np.insert(arr,1,values=woman,axis=1) file='历年总人口.csv' np.savetxt(file,arr,fmt='%i',delimiter=',',comments='',header='年份,年末总人口,男性人口,女性人口') x=np.loadtxt(file,dtype=np.int,,delimiter=',',skiprows=1) print(x)
import xlrd
import numpy as np
wb = xlrd.open_workbook("历年总人口.xls")
sheet = wb.sheet_by_index(0)
col_0 = sheet.col_values(0)[38:]
col_1 = sheet.col_values(1)[38:]
col_2 = sheet.col_values(2)[38:]
col_4 = sheet.col_values(4)[38:]
year = [int(c) for c in col_0]
total = [int(c) for c in col_1]
man = [int(c) for c in col_2]
woman = [int(c) for c in col_4]
m = len(year)
arr = np.array(year).reshape(m,1)
arr = np.insert(arr,1,values=total,axis=1)
arr = np.insert(arr,1,values=man,axis=1)
arr = np.insert(arr,1,values=woman,axis=1)
file='历年总人口.csv'
np.savetxt(file,arr,fmt='%i',delimiter=',',comments='',header='年份,年末总人口,男性人口,女性人口')
x = np.loadtxt(file,dtype=np.int,delimiter=',',skiprows=1)
print(x)
错误分析:File "C:\Users\g\AppData\Local\Temp/ipykernel_8532/925264442.py", line 26 x=np.loadtxt(file,dtype=np.int,,delimiter=',',skiprows=1) ^ SyntaxError: invalid syntax
这个错误提示是因为在 `np.loadtxt` 函数调用中有多余的逗号,导致语法无效。应该把多余的逗号删去即可。
下面是修改后的代码:
```python
import xlrd
import numpy as np
wb = xlrd.open_workbook("历年总人口.xls")
sheet = wb.sheet_by_index(0)
col_0 = sheet.col_values(0)[38:]
col_1 = sheet.col_values(1)[38:]
col_2 = sheet.col_values(2)[38:]
col_4 = sheet.col_values(4)[38:]
year = [int(c) for c in col_0]
total = [int(c) for c in col_1]
man = [int(c) for c in col_2]
woman = [int(c) for c in col_4]
m = len(year)
arr = np.array(year).reshape(m,1)
arr = np.insert(arr,1,values=total,axis=1)
arr = np.insert(arr,1,values=man,axis=1)
arr = np.insert(arr,1,values=woman,axis=1)
file='历年总人口.csv'
np.savetxt(file,arr,fmt='%i',delimiter=',',comments='',header='年份,年末总人口,男性人口,女性人口')
x = np.loadtxt(file,dtype=np.int,delimiter=',',skiprows=1)
print(x)
```