line wrapping problem

[S Borg]

Hello,

I am parsing text from one document to another. I have a scheme
similar to:

for x in myfoobar:
print >> mytextfile, "%s " % mydictionary[x], #all on same line
print >> mytextfile, '\n' #new line


I am getting line breaks before my explicit line break. Am I
unwittingly copying '\n' characters from the original file?
How should I fix this(What is the 'Pythonic' solution)?

thanks,
-S

[Fuzzyman]

Re: line wrapping problem


S Borg wrote:[color=blue]
> Hello,
>
> I am parsing text from one document to another. I have a scheme
> similar to:
>
> for x in myfoobar:
> print >> mytextfile, "%s " % mydictionary[x], #all on same line
> print >> mytextfile, '\n' #new line
>[/color]

You are using the print command to output the text to your file. This
will always put a '\n' at the end of lines (as well as your explicit)
one. The only time it doesn't do this is if the line ends with a
trailing comma, in which case it just adds a space.

The usual way is to write to yhour file object using :

mytextfile.writ e( mytextfile, "%s " % mydictionary[x],)

All the best,

Fuzzyman
http://www.voidspace.org.uk/python/index.shtml
[color=blue]
>
> I am getting line breaks before my explicit line break. Am I
> unwittingly copying '\n' characters from the original file?
> How should I fix this(What is the 'Pythonic' solution)?
>
> thanks,
> -S[/color]

[Juho Schultz]

Re: line wrapping problem

S Borg wrote:[color=blue]
> Hello,
>
> I am parsing text from one document to another. I have a scheme
> similar to:
>
> for x in myfoobar:
> print >> mytextfile, "%s " % mydictionary[x], #all on same line
> print >> mytextfile, '\n' #new line
>
>
> I am getting line breaks before my explicit line break. Am I
> unwittingly copying '\n' characters from the original file?
> How should I fix this(What is the 'Pythonic' solution)?
>
> thanks,
> -S
>[/color]

mytextfile.writ e("%s " % mydictionary[x])

should work. IMO file.write() is self-explanatory but "print >> file" is
a bit obscure.

[John Zenger]

Re: line wrapping problem

S Borg wrote:
[color=blue]
> print >> mytextfile, '\n' #new line[/color]

Wouldn't this print two line breaks--the one you specify in the string,
plus the one always added by print if there is no comma at the end of
the statement?

[ZeD]

Re: line wrapping problem

Ciao, Juho Schultz! Che stavi dicendo?
[color=blue]
> should work. IMO file.write() is self-explanatory but "print >> file" is
> a bit obscure.[/color]

is obscure only if you have never used a shell :)

--
Evangelion e' la storia yaoi di un angelo che vuole portarsi a letto un
ragazzo che si intreccia con la storia di un maturo professionista con il
complesso delle lolite... fatte in casa.
-- Lennier, 2006

[Peter Otten]

Re: line wrapping problem

S Borg wrote:
[color=blue]
> I am parsing text from one document to another. I have a scheme
> similar to:
>
> for x in myfoobar:
> print >> mytextfile, "%s " % mydictionary[x], #all on same line[/color]

print >> mytextfile # minimal fix
[color=blue]
> I am getting line breaks before my explicit line break. Am I
> unwittingly copying '\n' characters from the original file?
> How should I fix this(What is the 'Pythonic' solution)?[/color]

The trailing spaces are probably an artifact of your implementation. Here's
one way to avoid them:

print >> mytextfile, " ".join(str(mydi ctionary[x]) for x in myfoobar)

Peter

[Juho Schultz]

Re: line wrapping problem

ZeD wrote:[color=blue]
> Ciao, Juho Schultz! Che stavi dicendo?
>[/color]
Moro, ZeD! Kunhan pulisen. Should we stick to English?[color=blue]
>[color=green]
>>should work. IMO file.write() is self-explanatory but "print >> file" is
>>a bit obscure.[/color]
>
> is obscure only if you have never used a shell :)
>[/color]
(I have used the shell a bit. I started using Linux at work when 2.2
series kernels did not exist.)

Assume a newbie plays around with a piece code. If the code has
f.write(x) or print >> f,x - in which case the newbie is more likely to
break the code by rebinding f to something non-file? And in which case
he will more likely understand the error message, something like "f has
no write attribute"?

I am sure the >> can be useful - it is quick to add after a simple print
when you want less chatter and more logfiles. But IMO it is not
self-documenting. Having to very different uses for an operator in the
same language is sort of confusing.

[Kent Johnson]

Re: line wrapping problem

S Borg wrote:[color=blue]
> Hello,
>
> I am parsing text from one document to another. I have a scheme
> similar to:
>
> for x in myfoobar:
> print >> mytextfile, "%s " % mydictionary[x], #all on same line
> print >> mytextfile, '\n' #new line
>
>
> I am getting line breaks before my explicit line break. Am I
> unwittingly copying '\n' characters from the original file?[/color]

Where does mydictionary[x] come from? If it is from reading lines from a
file it may contain trailing newlines.

Also
print >> mytextfile, '\n'
will print two newlines, one explicit and one implicit in the print.

Kent