How to store data in array column wise from csv file in python

Question

Suppose I have a csv file containing five columns each having 200 data. I have used these two codes but either of those storing row wise data. Can anyone tell me how to store each column as an individual array in python directly form .csv file?

Code1:

import csv
with open("figure1_plotdata.csv") as f:
    reader = csv.reader(f)
    next(reader)
    data = [r for r in reader]
print (data)

Code2:

from numpy import genfromtxt
my_data = genfromtxt('figure1_plotdata.csv', delimiter=',')
print (my_data)

please follow the link ( loco.lab.asu.edu/edges/edges-data-release ) to download the data. — Ankita Bera
– Ankita Bera, Commented Jul 19, 2018 at 8:14

Sreeram TP · Accepted Answer · 2018-07-12 07:26:41Z

1

If you want to convert a CSV file to list where individual list corresponds to a column, you can use pandas to load the csv and apply transpose to get the desired result.

It can be done like this.

import pandas as pd

df = pd.read_csv('your_file_name.csv')

data_list = df.T.values.tolist()

print(data_list)

Sample dataframe

Result

[[1, 2, 3], [10, 20, 30], [11, 22, 33]]

answered Jul 12, 2018 at 7:26

Sreeram TP

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1 Comment

Ankita Bera Over a year ago

Thanks for the simplest solution, it works perfectly for me!

Bruno Vermeulen · Accepted Answer · 2018-07-12 08:25:19Z

0

Try something like this. Store the data in the csv file in a 2 dimensional data array data[i][j] with i being the column and j the row, both indices starting at 0. (Basically the originally data being transposed)

import csv

file_name = 'figure1_plotdata.csv'
data = [[] for i in range(5)]

with open(file_name) as csvfile:
    csvdata = csv.reader(csvfile, dialect='excel', delimiter=',')

    '''  store column value in a 2 dimensional data array data[i][j] 
         with i being the column and j the row '''
    for row in csvdata:
        for i, column in enumerate(row):
            data[i].append(column)

for i, column in enumerate(data):
    for j, value in enumerate(column):
        print(f'row {j}, column {i}: {value}')

edited Jul 12, 2018 at 8:25

answered Jul 12, 2018 at 8:04

Bruno Vermeulen

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