How to read a file line by line into a list with Python

with open(fname) as f:
    content = f.readlines()
# you may also want to remove whitespace characters like `\n` at the end of each line
content = [x.strip() for x in content] 

I'm guessing that you meant list and not array.

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.}

This is more explicit than necessary, but does what you want.

with open("file.txt", "r") as ins:
    array = []
    for line in ins:
        array.append(line)

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

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

If you want the \n included:

with open(fname) as f:
    content = f.readlines()

If you do not want \n included:

with open(fname) as f:
    content = f.read().splitlines()

You could simply do the following, as has been suggested:

with open('/your/path/file') as f:
    my_lines = f.readlines()

Note that this approach has 2 downsides:

1) You store all the lines in memory. In the general case, this is a very bad idea. The file could be very large, and you could run out of memory. Even if it's not large, it is simply a waste of memory.

2) This does not allow processing of each line as you read them. So if you process your lines after this, it is not efficient (requires two passes rather than one).

A better approach for the general case would be the following:

with open('/your/path/file') as f:
    for line in f:
        process(line)

Where you define your process function any way you want. For example:

def process(line):
    if 'save the world' in line.lower():
         superman.save_the_world()

(The implementation of the Superman class is left as an exercise for you).

This will work nicely for any file size and you go through your file in just 1 pass. This is typically how generic parsers will work.

This should encapsulate the open command.

array = []
with open("file.txt", "r") as f:
  for line in f:
    array.append(line)

Clean and Pythonic Way of Reading the Lines of a File Into a List

First and foremost, you should focus on opening your file and reading its contents in an efficient and pythonic way. Here is an example of the way I personally DO NOT prefer:

infile = open('my_file.txt', 'r')  # Open the file for reading.

data = infile.read()  # Read the contents of the file.

infile.close()  # Close the file since we're done using it.

Instead, I prefer the below method of opening files for both reading and writing as it is very clean, and does not require an extra step of closing the file once you are done using it. In the statement below, we're opening the file for reading, and assigning it to the variable 'infile.' Once the code within this statement has finished running, the file will be automatically closed.

# Open the file for reading.
with open('my_file.txt', 'r') as infile:

    data = infile.read()  # Read the contents of the file into memory.

Now we need to focus on bringing this data into a Python List because they are iterable, efficient, and flexible. In your case, the desired goal is to bring each line of the text file into a separate element. To accomplish this, we will use the splitlines() method as follows:

# Return a list of the lines, breaking at line boundaries.
my_list = data.splitlines()

The Final Product:

# Open the file for reading.
with open('my_file.txt', 'r') as infile:

    data = infile.read()  # Read the contents of the file into memory.

# Return a list of the lines, breaking at line boundaries.
my_list = data.splitlines()

Testing Our Code:

• Contents of the text file:

     A fost odatã ca-n povesti,
     A fost ca niciodatã,
     Din rude mãri împãrãtesti,
     O prea frumoasã fatã.

• Print statements for testing purposes:

    print my_list  # Print the list.

    # Print each line in the list.
    for line in my_list:
        print line

    # Print the fourth element in this list.
    print my_list[3]

• Output (different-looking because of unicode characters):

     ['A fost odat\xc3\xa3 ca-n povesti,', 'A fost ca niciodat\xc3\xa3,',
     'Din rude m\xc3\xa3ri \xc3\xaemp\xc3\xa3r\xc3\xa3testi,', 'O prea
     frumoas\xc3\xa3 fat\xc3\xa3.']

     A fost odatã ca-n povesti, A fost ca niciodatã, Din rude mãri
     împãrãtesti, O prea frumoasã fatã.

     O prea frumoasã fatã.

As simple as it can get:

for line in open("myfile.txt") :
    print line.rstrip('\n') # .rstrip('\n') removes the line break

Another option is numpy.genfromtxt, e.g:

import numpy as np
data = np.genfromtxt("yourfile.dat",delimiter="\n")

This will make data a numpy array with as many rows as are in your file

Here's one more option by using list comprehensions on files;

lines = [line.rstrip() for line in open('file.txt')]

This should be more efficient way as the most of the work is done inside the Python interpreter.

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

The simplest way to do it

A simple way is to:

1. Read the whole file as a string
2. Split the string line by line

In one line, that would give:

lines = open('C:/path/file.txt').read().splitlines()

I'd do it like this.

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

f = open("your_file.txt",'r')
out = f.readlines() # will append in the list out

Now variable out is a list (array) of what you want. You could either do:

for line in out:
    print line

or

for line in f:
    print line

you'll get the same results.

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

inp = file.txt
data = open(inp)
dat = data.read()
lst = dat.splitlines()
print lst

In the output you will have the list of lines.

An real easy way:

with open(file) as g: stuff = g.readlines()

if you want to make it a fully fledged program, type this in:

import time
file = raw_input ("Enter EXACT file name: ")
with open(file) as g:
    stuff = g.readlines()
print (stuff)
exit = raw_input("Press enter when you are done.")

For some reason, it doesn't read .py files properly.

To my knowledge Python doesn't have a native array data structure. But it do supports list data structure which is much simpler to use than a Array.

array = [] #declaring a list with name '**array**' 
with open(PATH,'r') as reader :
    for line in reader :
        array.append(line)

Could also use the loadtxt command in numpy. This checks for fewer conditions than genfromtxt so it may be faster.

import numpy 
data = numpy.loadtxt(filename,delimiter="\n")

How about this:

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

data is dataframe type, and use values to get ndarray, you also can get list by use array.tolist() Hope this can help you a little:)

lines = list(open("dict.lst", "r"))
linesSanitized = map(lambda each:each.strip("\n"), lines)
print linesSanitized

with open(fname) as fo:
        data=fo.read().replace('\n', ' ').replace (',', ' ')

This should answer your question. The replace function will act as delimiter to strip the file.

How about:

fp = open("filename")
content = fp.read();
lines = content.split("\n")

Declare a unix like method

def cat(filename):
    with open(filename) as f:
        return f.read().decode('utf-8')

And just invoke it to get the file content.

content = cat(filename)