String formatting in python isn't working as expected

Question

I'm building a string via the following:

pagination +='<li>''<a href="/main/?page=%(current_link)s'+link+'">%(current)s</a></li>' % \
                     {'current_link': current_link, 'current': current_link}

When viewing the page in the browser, the text shows up fine but the link points to "..%(current_link)s...". I've tried naming both of them 'current_link' in the string itself but that didn't work so I tried the approach above.

Any suggestions?

Rob Wouters · Accepted Answer · 2012-01-16 15:06:30Z

3

The problem is you have separated the string, making the % operator only work on the last part.

Try it like this:

pagination +='<li><a href="/main/?page=%(current_link)s>%(current)s</a></li>' % \
                     {'current_link': current_link, 'current': current_link}

Or if you intended the link variable in there like so:

pagination +='<li><a href="/main/?page=%(current_link)s%(link)s>%(current)s</a></li>' % \
                     {'link': link, 'current_link': current_link, 'current': current_link}

answered Jan 16, 2012 at 15:06

Rob Wouters

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4 Comments

user1100778 Over a year ago

Okay thanks I'll try that. How did you get the HTML to show up in the question though? I was about to delete the question because I couldn't get it to show up

Rob Wouters Over a year ago

@user1100778, if you start a line with four spaces it will show up as code. Read here for other formatting help: stackoverflow.com/editing-help

user1100778 Over a year ago

Okay I tried it out and it works great and makes sense. Thanks everyone!

Rob Wouters Over a year ago

@user1100778, you can mark the question as solved if it helped you :)

Dirk · Accepted Answer · 2012-01-16 15:08:51Z

1

Hm. You are mixing concatenation with + and formatting with %, and I think, this is a matter of operator precedence: % binds stronger than +, so

("%(a)s" + "%(b)s" % { 'a': 'A', 'b': 'B' }) == '%(a)sB'

answered Jan 16, 2012 at 15:08

Dirk

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Comments

Wooble · Accepted Answer · 2012-01-16 15:07:23Z

0

Don't combine cramming strings together with no operator ('foo''bar'), concatenating with +, and formatting with %. You're only formatting the final string.

answered Jan 16, 2012 at 15:07

Wooble

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