Python pandas read list in list data type from csv file

Question

I have a csv file, like this:

A       B
aaa     [['a1','b1'],['a2','b2']]
bbb     [['a3','b3']]

I tried to read this file into python. And I want the 'B' column in list data type.
I tried pd.read_csv('filename.csv'), what I got is "[['a1','b1'],['a2','b2']]" in str type, not in list type.
And I also tried pd.read_csv('filename.csv', converters={'B':list}), what I got here is like: [[, [',a','1,','b,'...., not the list I want.
Could you tell me how to read the list from a csv file directly? Thank you so much.

can you share csv file

Argus Malware
– Argus Malware

2017-11-04 06:44:29 +00:00
Commented Nov 4, 2017 at 6:44 — Argus Malware
– Argus Malware, Commented Nov 4, 2017 at 6:44

Elisha · Accepted Answer · 2017-11-04 06:55:01Z

3

The issue here is caused by the serialization format of the list in column B. It is stored as a string representation of the list. In order to recover a python list back from the string, you can use eval as a converter:

df = pd.read_csv(source, converters={'B': eval})

answered Nov 4, 2017 at 6:55

Elisha

23.8k6 gold badges65 silver badges77 bronze badges

Sign up to request clarification or add additional context in comments.

Comments

Argus Malware · Accepted Answer · 2017-11-04 06:46:27Z

0

to read list you should try this

import csv
with open('filename.csv', 'rb') as f:
    reader = csv.reader(f)
    your_list = list(reader)

print your_list

answered Nov 4, 2017 at 6:46

Argus Malware

7877 silver badges19 bronze badges

Comments

rissorg · Accepted Answer · 2023-08-17 09:05:27Z

0

I use pandas to handle file easily. If you can decide what gets in your file, you could also choose to store something like this:

A,B
aaa,a1 b1 + a2 b2
bbb,a3 b3

Then you can simply read your file and use the power of the split function which will:

split your string with the seperator of your choice (white space by default)
return the result in a list object.

For your second colum of the first row, you can simply run split once with the white space as a seperator and run it again with '+' as a seperator.

You can find more details on split here https://www.w3schools.com/python/ref_string_split.asp

import pandas

df = pandas.read_csv('my_file.csv')
for row in df.itertuples():
  my_list = row.A.split()

edited Aug 17, 2023 at 9:05

answered Aug 17, 2023 at 9:02

rissorg

11 bronze badge

Collectives™ on Stack Overflow

Python pandas read list in list data type from csv file

3 Answers 3

Comments

Comments

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

3 Answers 3

Comments

Comments

Comments

Your Answer

Sign up or log in

Post as a guest

Related