How to read a file line-by-line into a list?

Question

How do I read every line of a file in Python and store each line as an element in a list?

I want to read the file line by line and append each line to the end of the list.

Answer 1

I'd do it like this.

lines = []
with open("myfile.txt") as f:
    for line in f:
        lines.append(line)

Answer 2

Use this:

import pandas as pd
data = pd.read_csv(filename) # You can also add parameters such as header, sep, etc.
array = data.values

data is a dataframe type, and uses values to get ndarray. You can also get a list by using array.tolist().

Answer 3

See Input and Ouput:

with open('filename') as f:
    lines = f.readlines()

or with stripping the newline character:

lines = [line.rstrip('\n') for line in open('filename')]

^{Editor's note: This answer's original whitespace-stripping command, line.strip(), as implied by Janus Troelsen's comment, would remove all leading and trailing whitespace, not just the trailing \n.}

Answer 4

This will yield an "array" of lines from the file.

lines = tuple(open(filename, 'r'))

Answer 5

Just use the splitlines() functions. Here is an example.

inp = "file.txt"
data = open(inp)
dat = data.read()
lst = dat.splitlines()
print lst
# print(lst) # for python 3

In the output you will have the list of lines.

Answer 6

If you'd like to read a file from the command line or from stdin, you can also use the fileinput module:

# reader.py
import fileinput

content = []
for line in fileinput.input():
    content.append(line.strip())

fileinput.close()

Pass files to it like so:

$ python reader.py textfile.txt 

Read more here: http://docs.python.org/2/library/fileinput.html