“ Numpy” TypeError：不理解数据类型“字符串”

Question

I am a newbie trying to learn data visuallizaion using python. Actually, I was just trying to follow the example given by a cookbook , like:

import numpy
import os
os.chdir("Home/Desktop/Temporal_folder")
data = numpy.loadtxt ('ch02-data.csv', dtype= 'string', delimiter=',')
print (data)

but somehow it did not work out:

Traceback (most recent call last):
  File "Home/PycharmProjects/Learning/Datavisuallization.py", line 5, in <module>
    data = numpy.loadtxt ('ch02-data.csv', dtype= 'string', delimiter=',')
  File "Home/anaconda/lib/python3.6/site-packages/numpy/lib/npyio.py", line 930, in loadtxt
    dtype = np.dtype(dtype)
TypeError: data type "string" not understood

this is the data I used: "ch02-data.csv"

there were some similar issues posted , but I am not sure I understood what the answer tried to explain. Also, I checked the manual of numpy.loadtext() , still the answer does not seem to be obvious to me... any suggestion? https://docs.scipy.org/doc/numpy/reference/generated/numpy.loadtxt.html

Answer 1

尝试使用dtype ='str'而不是dtype ='string'。

Answer 2

Actually, it works well in Python2, but it doesn't work in Python 3.x, you can try numpy.str

In Python 2, there's no problem:

>>> import numpy as np
>>> np.__version__
'1.12.0'
>>> np.dtype('string')
dtype('S')
>>> np.dtype('str')
dtype('S')

In Python 3, this throw an exception:

>>> import numpy as np
>>> np.__version__
'1.11.3'
>>> np.dtype('string')
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
TypeError: data type "string" not understood
>>> np.dtype('str')
dtype('<U')

you can see more details from this issue .