problems iterating over a files lines

[Jesse Noller]

I am a relative newbie to python and I am having issues trying to
iterate over the lines of a file.

I have a text file - foo.bar inside of this file are lines of text:

x-3411342
y-1324123
w-2314121

Each with a trailing \n to designate the end of the line.

I am trying to read this file into python - which is simply in and of
itself, however:

file = open("foo.bar", "rb")
while 1:
lines = file.open().split('\n'):
if not lines:
break
for lines in lines:
key = line
get.key(key)
results = [key, get.up, get.down]
file.close()

Appends an extra "blank" line to the list of lines, which causes the
program to crash - secondly, I've looked at about 20 examples, and all
of them (including this one) suffer from the problem of looping over
the lines for the number of lines.

What I want to do is open the contents of the file - read the line and
set a variable - key, and for each line in the file, I want to do
something with that key - but only once. So I want to read in a line,
set to a variable, do something, print, and then do it for the next
line.


Any help is appreciated. Thank you.

 

[James Henderson]

I am a relative newbie to python and I am having issues trying to
iterate over the lines of a file.

I have a text file - foo.bar inside of this file are lines of text:

x-3411342
y-1324123
w-2314121

Each with a trailing \n to designate the end of the line.

I am trying to read this file into python - which is simply in and of
itself, however:

file = open("foo.bar", "rb")
while 1:
lines = file.open().split('\n'):
if not lines:
break
for lines in lines:
key = line
get.key(key)
results = [key, get.up, get.down]
file.close()

Appends an extra "blank" line to the list of lines, which causes the
program to crash - secondly, I've looked at about 20 examples, and all
of them (including this one) suffer from the problem of looping over
the lines for the number of lines.

What I want to do is open the contents of the file - read the line and
set a variable - key, and for each line in the file, I want to do
something with that key - but only once. So I want to read in a line,
set to a variable, do something, print, and then do it for the next
line.

First I take it:

lines = file.open().split('\n'):

should have been:

lines = file.read().split('\n'):

If you used file.read().splitlines() instead you would avoid the extra blank
line.

A much better way to iterate line-by-line through the list is simply:

for line in file("foo.bar", "rb"):
# do something to line

(I'm using the built-in file() function - strictly type - which is the new
name for open().)

I don't know where your "get" comes from so I can't help you with the rest.

James

 

[James Henderson]

If you used file.read().splitlines() instead you would avoid the extra
blank line.

Or even file.readlines(). D'oh!

Though this keeps the newlines on the end of each file.