读取csv文件以列出

Question

I want to export a nested list, then import it without losing the shape of the list. The list is a nested list, each inner list has 10 elements, there are 10000 inner lists construct a large list.

The inner lists look like this: the shape is 1 x 10

    [array([  1, 2, 3, 4, 5
              6, 7, 8, 9, 10 ],
    array([ 21, 22, 23, 24, 25
           26, 27, 28, 29, 30 ]

I exported it to csv. In csv, it becomes like this. Each inner list is in one cell

['[ 1  2  3  4  5\n 6  7  8  9  10]']
['[ 21  22  23  24  25\n 26  27  28  29  30]']

Then I imported the csv to list. However the shape becomes 1 x 1 I wish to make it into 1 x 10 shape, ideally same as the original list format I exported. how to achieve this ?

The code I used for exporting list: (X is the list)

import csv
with open('X.csv', "w") as output:
    writer = csv.writer(output, lineterminator='\n')
    for val in X:
        writer.writerow([val])  

The code I used for importing csv: (X is the list)

with open('X.csv', 'r') as f:
    reader = csv.reader(f)
    X = list(reader)

Thank you in advanced !

Answer 1

Try This,

import pandas as pd
df = pd.read_csv('filename.csv')
list_ = df.values.tolist()

Answer 2

I would suggest you maybe save it as a pickle or a DataFrame instead to you don't need to fiddle about so much when reading it back in. Pickles save in the memory representation used by python.

import pickle
pickle.dump(X, open('X.pkl', "wb"))
X_loaded = pickle.load(open('X.pkl', "rb"))