\r mangles variable assignment in python

Question

I have a very unusual problem. Am working with python 2.6 to make API calls to a bulkSMS gateway. Now if I make the call like this

req = urllib2.Request(url)
urllib2.urlopen(req).read()

I get this(correct) response printed back to terminal

'<RESPONSE>\r<status>-4</status>\r<credits>31.3403</credits>\r</RESPONSE>'

But when I assign this output to variable,

reply = urllib2.urlopen(req).read()

I get this(incorrect) response when I print to terminal

print reply
</RESPONSE>.3403</credits>

Anybody care to explain what's going on here?

RocketDonkey · Accepted Answer · 2012-12-20 02:36:19Z

3

It is interpreting the \r characters as a special character (ASCII carriage return - see here for some examples) and removing them from the string on printing. To include them, you can use the string-escape encoding:

In [1]: resp = '<RESPONSE>\r<status>-4</status>\r<credits>31.3403</credits>\r</RESPONSE>'

In [2]: print resp
</RESPONSE>.3403</credits>

In [3]: print resp.encode('string-escape')
<RESPONSE>\r<status>-4</status>\r<credits>31.3403</credits>\r</RESPONSE>

Not directly applicable in your case, but another way this kind of escaping is done is to prefix a string with r, which makes it a 'raw' string and keeps the backslashes (you'll see this a lot with regular expression):

In [4]: resp = r'<RESPONSE>\r<status>-4</status>\r<credits>31.3403</credits>\r</RESPONSE>'

In [5]: print resp
<RESPONSE>\r<status>-4</status>\r<credits>31.3403</credits>\r</RESPONSE>

answered Dec 20, 2012 at 2:36

RocketDonkey

37.4k8 gold badges83 silver badges84 bronze badges

Sign up to request clarification or add additional context in comments.

2 Comments

user1048839 Over a year ago

Thanks, this worked for me, while still preserving the content of the variable in it's original form.

RocketDonkey Over a year ago

@user1048839 Awesome, glad it worked out for you. Good luck with everything!

BrenBarn · Accepted Answer · 2012-12-20 02:39:24Z

2

The string contains the correct data, it's just printing in a weird way. \r is a carriage return, which some systems interpret as "go back to the beginning of the line and start overwriting from there". So you see "</RESPONSE>" plus data from the previous line that was longer (and so wasn't overwritten).

It's a bit odd that your data contain \r since it's not that common as a line-ending convention these days.

You could print repr(response) to see the response without \r interpreted this way. Any processing you do on the line should work fine since all the data is there, it's just not printing.

answered Dec 20, 2012 at 2:39

BrenBarn

253k39 gold badges421 silver badges392 bronze badges

3 Comments

RocketDonkey Over a year ago

+1 - good point about the resetting of the position back to the beginning of the line.

Blckknght Over a year ago

Yep, this is exactly the issue. If necessary, you can fix the string with reply.replace("\r", "\n"), which will put newlines in place of the carriage returns.

user1048839 Over a year ago

Am very tempted to replace the offending character 'r' but that would essentially mean changing the content of the reply which I would like to stay as close to original as possible since I will be using it across other functions too.

Collectives™ on Stack Overflow

\r mangles variable assignment in python

2 Answers 2

2 Comments

3 Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

2 Comments

3 Comments

Your Answer

Sign up or log in

Post as a guest

Related