How to read a file without newlines?

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How to read a file without newlines?

In Python, calling

temp = open(filename,'r').readlines()

results in a list in which each element is a line in the file. It’s a little stupid but still: readlines() also writes newline character to each element, something I do not wish to happen.

How can I avoid it?

Asked By: Yotam

||

Answer #1:

You can read the whole file and split lines using str.splitlines:

temp = file.read().splitlines()

Or you can strip the newline by hand:

temp = [line[:-1] for line in file]

Note: this last solution only works if the file ends with a newline, otherwise the last line will lose a character.

This assumption is true in most cases (especially for files created by text editors, which often do add an ending newline anyway).

If you want to avoid this you can add a newline at the end of file:

with open(the_file, 'r+') as f:
    f.seek(-1, 2)  # go at the end of the file
    if f.read(1) != 'n':
        # add missing newline if not already present
        f.write('n')
        f.flush()
        f.seek(0)
    lines = [line[:-1] for line in f]

Or a simpler alternative is to strip the newline instead:

[line.rstrip('n') for line in file]

Or even, although pretty unreadable:

[line[:-(line[-1] == 'n') or len(line)+1] for line in file]

Which exploits the fact that the return value of or isn’t a boolean, but the object that was evaluated true or false.


The readlines method is actually equivalent to:

def readlines(self):
    lines = []
    for line in iter(self.readline, ''):
        lines.append(line)
    return lines
# or equivalently
def readlines(self):
    lines = []
    while True:
        line = self.readline()
        if not line:
            break
        lines.append(line)
    return lines

Since readline() keeps the newline also readlines() keeps it.

Note: for symmetry to readlines() the writelines() method does not add ending newlines, so f2.writelines(f.readlines()) produces an exact copy of f in f2.

Answered By: Bakuriu

Answer #2:

temp = open(filename,'r').read().split('n')
Answered By: vivek

Answer #3:

another example:

Reading file one row at the time. Removing unwanted chars with from end of the string str.rstrip(chars)

with open(filename, 'r') as fileobj:
    for row in fileobj:
        print( row.rstrip('n') )

see also str.strip([chars]) and str.lstrip([chars])

(python >= 2.0)

Answered By: O-9

Answer #4:

temp = open(filename,'r').read().splitlines()
Answered By: Marcel

Answer #5:

I think this is the best option.

temp = [line.strip() for line in file.readlines()]
Answered By: RENZO

Answer #6:

Try this:

u=open("url.txt","r")
url=u.read().replace('n','')
print(url)
Answered By: Nitesh Soni

Answer #7:

my_file = open("first_file.txt", "r")
for line in my_file.readlines():
    if line[-1:] == "n":
        print(line[:-1])
    else:
        print(line)
my_file.close()
Answered By: Necriss

Answer #8:

import csv
with open(filename) as f:
    csvreader = csv.reader(f)
    for line in csvreader:
         print(line[0])
Answered By: srus

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