In Python, calling
temp = open(filename,'r').readlines()
results in a list in which each element is a line in the file. Its 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?
You can read the whole file and split lines using
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.
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
readline() keeps the newline also
readlines() keeps it.
Note: for symmetry to
writelines() method does not add ending newlines, so
f2.writelines(f.readlines()) produces an exact copy of
temp = open(filename,'r').read().split('\n')