在python上传CSV文件的问题

Question

I have some problem with uploding excel data in python.

Excel :

Code used to upload:

import pandas as pd
from google.colab import files
#uploaded = files.upload()
import io
df2 = pd.read_csv(io.BytesIO(uploaded['nodes.csv']),index_col=0)
print (df2)

Result :

Can you kindly help me?

Answer 1

You said you wanted to convert the imported data to a numpy array, you could do so by doing the following without using pandas:

import numpy as np
arr = np.genfromtxt('nodes.csv', delimiter=',')
print(arr)

Check the documentation: https://numpy.org/doc/stable/reference/generated/numpy.genfromtxt.html

Answer 2

If you have a csv-file file.csv

0,0
2,0
4,0
1,1.732051
3,1.732051

then

df = pd.read_csv("file.csv", index_col=0)

does produce

df =
        0.1
0          
2  0.000000
4  0.000000
1  1.732051
3  1.732051

Why is that: There are two 0 s in the first row and Pandas is mangling the dupes because the row is used for labels. The 0.1 isn't a number, it's a string ( print(df.columns) will show Index(['0.1'], dtype='object') ). If your file would look like

0,1
2,0
4,0
1,1.732051
3,1.732051

then this wouldn't happen, the output would look like

          1
0          
2  0.000000
4  0.000000
1  1.732051
3  1.732051

If your goal is NumPy array, then

arr = pd.read_csv("file.csv", header=None).values

leads to

array([[0.      , 0.      ],
       [2.      , 0.      ],
       [4.      , 0.      ],
       [1.      , 1.732051],
       [3.      , 1.732051]])