Python 3: Write newlines to HTML

Question

I have upgraded to Python 3 and can't figure out how to convert backslash escaped newlines to HTML.

The browser renders the backslashes literally, so "\n" has no effect on the HTML source. As a result, my source page is all in one long line and impossible to diagnose.

This does not work since these are "HTML entities", ASCII codes for rendered characters. So my source page ends up looking like this: New · — Gnarlodious, Nov 22 '09 at 02:37

score 7 · Answer 1 · answered Nov 21 '09 at 17:21

7

normally I do like this s=s.replace("\n","<br />\n")

because

<br /> is needed in web page display and

\n is needed in source display.

just my 2 cents

answered Nov 21 '09 at 17:21

YOU

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I would suggest to first replace \r\n with \n and then \n with
so you don't end up with some \r in your string. – Brian R. Bondy Nov 21 '09 at 17:49
This does not work since my output does not already have newlines in it. In any case, apparently Python 3 does not convert UNIX style escaped characters into the appropriate ASCII characters. – Gnarlodious Nov 22 '09 at 02:41
how about `=s.replace(" ","\n")` Gnarlodious? – YOU Nov 22 '09 at 04:09
@Gnarlodious: The question "backslash escaped newlines". Does that mean "\\n"? A backslash character (\) and an n? If so, `replace( "\\n", "
" )` would work. – S.Lott Nov 22 '09 at 05:02
@S.Lott - G'odious is saying that his HTML source has *no* newlines in it, so the substitution string should put in a newline too. In fact, it's not clear that he/she *want* the HTML `
`s in there, just not all the HTML on one line. I think the desired code is `s = s.replace(r'\n','\n')`. – PaulMcG Nov 22 '09 at 10:49

score 1 · Accepted Answer · answered Dec 02 '09 at 18:00

1

The solution is:

#!/usr/bin/python 
 import sys 
 def print(s): return sys.stdout.buffer.write(s.encode('utf-8'))
 print("Content-type:text/plain;charset=utf-8\n\n") 
 print('晉\n')

See the original discussion here: http://groups.google.com/group/comp.lang.python/msg/f8bba45e55fe605c

answered Dec 02 '09 at 18:00

Gnarlodious

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If you mark this answer as correct, more people will see it! :) – Chris Cooper Aug 20 '13 at 18:59

score 0 · Answer 3 · answered Nov 21 '09 at 17:16

0

Maybe I don't get it, but isn't <br /> some kind of newline for HTML?

s = "Hello HTML\n"
to_render = s.replace("\n", "<br />")

If you render something with mimetype "text/plain" \newlines should work.

answered Nov 21 '09 at 17:16

miku

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Yes, in fact newlines ARE working! It seems that I am saying

print("Content-type:text/html\n\n", HTML.encode("utf-8"))

so the conversion to UTF8 is wiping out my newlines! And actually, Python 3 is all about UTF8, so that conversion is unnecessary. However, removing the conversion gives me error:

UnicodeEncodeError: 'ascii' codec can't encode character '\u8e47' in position 14525: ordinal not in range(128)
So what is happening?

Can anyone tell me how to format text on this site?

– Gnarlodious Nov 22 '09 at 02:55

score 0 · Answer 4 · answered Dec 13 '17 at 14:37

0

If you are using Django, this answer will be helpful.

It's about how you render the page and whether you escape HTML or no.

answered Dec 13 '17 at 14:37

gevra

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score 0 · Answer 5 · answered Jan 19 '19 at 16:47

0

Since I have solved basic Markdown, I have resolved the new lines with a regular expression.

import re
br = re.compile(r"(\r\n|\r|\n)")  # Supports CRLF, LF, CR
content = br.sub(r"<br />\n", content)  # \n for JavaScript

answered Jan 19 '19 at 16:47

Geekmoss

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score -1 · Answer 6 · answered Nov 21 '09 at 17:22

Print() should add a newline by default - unless you tell it otherwise. However there have been other changes in Python 3:

Old: print "The answer is", 2*2
New: print("The answer is", 2*2)

Old: print x,           # Trailing comma suppresses newline
New: print(x, end=" ")  # Appends a space instead of a newline

Old: print              # Prints a newline
New: print()            # You must call the function!

Old: print >>sys.stderr, "fatal error"
New: print("fatal error", file=sys.stderr)

Old: print (x, y)       # prints repr((x, y))
New: print((x, y))      # Not the same as print(x, y)!

Old = Python 2.5, New = Python 3.

More details here: http://docs.python.org/3.1/whatsnew/3.0.html

This does not work since I am assembling strings and returning the result. If I were printing directly from the script it might be OK. — Gnarlodious, Nov 22 '09 at 02:43

Python 3: Write newlines to HTML

6 Answers6