将列表列表另存为csv文件python中的行

Question

I have a list of lists as follows:

L = [[1, 2, 3], [4, 5, 6], [7, 8, 9]]

I want to save this in a csv file as follows:

index, name, lists

0, 'name1', [1, 2, 3]
1, 'name2', [4, 5, 6]
2, 'name3', [7, 8, 9]

If this is possible, then how should I do this with python?

Answer 1

If you leave the default kwargs for csv.writer it will recognize that the list has commas in the string representation of the list and automatically quote it for you.

import csv
with open('filename.csv', 'w') as f:
   L = [[1, 2, 3], [4, 5, 6], [7, 8, 9]]
   fieldnames = ['index', 'name', 'lists']
   writer = csv.writer(f)
   writer.writerow(fieldnames)
   for i, row in enumerate(L):
       writer.writerow([str(i), 'name{}'.format(i), row])

If you look at filename.csv you get

index,name,lists
0,name_0,"[1, 2, 3]"
1,name_1,"[4, 5, 6]"
2,name_2,"[7, 8, 9]"

Answer 2

You can use Pandas to assemble your data into a data frame and easily output it as a CSV file:

import pandas as pd

L = [[1, 2, 3], [4, 5, 6], [7, 8, 9]]
name = ['name1', 'name2', 'name3']

df = pd.DataFrame({'name': name, 'lists': L})
print(df)

df.to_csv('file.csv', index_label='index')

    name      lists
0  name1  [1, 2, 3]
1  name2  [4, 5, 6]
2  name3  [7, 8, 9]

Answer 3

You only have 3 rows in your sheet, is that correct? If so, Pandas.DataFrame would be a great fit for this issue.

#import pandas moudle first
import pandas as pd  


#If you want to add `index` as the column name
index=[0,1,2]
name =['name 0','name 1','name 2']
#This is your original list in Python
L = [[1, 2, 3], [4, 5, 6], [7, 8, 9]]

#Using pd.DataFrame function to reformat the list into table
#Name the first column as 'index', the second column as 'name', and the last column as'lists'

table = pd.DataFrame({'index':index,
                      'name':name,
                      'lists':L})

#Write DataFrame to a comma-separated values (csv) file
table.to_csv('L.csv', index=False)

If you try to print the result, it will show like following (apologize I don't know how to embed the table properly)

 <table> <tr> <td></td> <td>index</td> <td>name</td> <td>list</td> </tr> <tr> <td>0</td> <td>0</td> <td>name 1</td> <td>[1, 2, 3]</td> </tr> <tr> <td>1</td> <td>1</td> <td>name 2</td> <td>[4, 5, 6]</td> </tr> <tr> <td>1</td> <td>1</td> <td>name 3</td> <td>[7, 8, 9]</td> </tr> </table>