Save list with nested list into CSV

[SpongeB0B]

Hi everyone,

I would like to save a list (with nested list inside) to a CSV

the problem is that the nested list are quoted with " sign in the csv file.

and when I read back the file the nested list are no longer lists but string :/

any ideas to solve this problem ?
 

import csv

y = [1,10]

data = [
    ['John','Doe',y],
    ['Gordon','Freeman',[5,20]],
    ['Lara','Croft',[7,35]],
]

print(data[0][2]) #give [1,10]
print(len(data[1][2])) #give 2 <------

with open('28_test.csv', 'w', newline='') as output:
    writer = csv.writer(output)
    writer.writerows(data)



readback = []
with open('28_test.csv', 'r') as readed:
    reader = csv.reader(readed)
    readback = list(reader)

print('data:',data)
print('readback:',readback)
print(readback[0][2]) #give [1,10]
print(len(readback[1][2])) #give 7 <------

[bowlofred]

CSVs are simple.  There's no (standard) way to store complex data structures with them like lists.   You could create your own protocol to do so, but it wouldn't be understood by other CSV parsers.

• Save in some other file format (JSON, YAML, etc.)
  
• If you only have one, put the nested list at the end (and starting at a particular column).  After you read in the CSV, combine all the columns after that point into a single list via a comprehension.