How to read a text file into a list or an array with Python

Question

I am trying to read the lines of a text file into a list or array in python. I just need to be able to individually access any item in the list or array after it is created.

The text file is formatted as follows:

0,0,200,0,53,1,0,255,...,0.

Where the ... is above, there actual text file has hundreds or thousands more items.

I'm using the following code to try to read the file into a list:

text_file = open("filename.dat", "r")
lines = text_file.readlines()
print lines
print len(lines)
text_file.close()

The output I get is:

['0,0,200,0,53,1,0,255,...,0.']
1

Apparently it is reading the entire file into a list of just one item, rather than a list of individual items. What am I doing wrong?

Answer 1

You will have to split your string into a list of values using split()

So,

lines = text_file.read().split(',')

EDIT: I didn't realise there would be so much traction to this. Here's a more idiomatic approach.

import csv
with open('filename.csv', 'r') as fd:
    reader = csv.reader(fd)
    for row in reader:
        # do something