String substitution - unsupported format character '}'
Question
I'm trying to do some string substitution for html/javascript templating, however when the page string variable has a curly brace in the code, I get the error of "ValueError: unsupported format character '}' (0x7d)". If I don't have any string substitution everything works fine. Thanks for reading!
import webapp2
page = """
<html>
<style type="text/css">
html { height: 100% }
body { height: 100%; margin: 0; padding: 0 }
#map_canvas { height: 100% }
</style>
%(say)s
</html>
"""
class MainHandler(webapp2.RequestHandler):
def write_form(self, say):
self.response.out.write(page % { "say": say })
def get(self):
self.write_form("hello")
app = webapp2.WSGIApplication([('/', MainHandler)],
debug=True)
1 answers
solution1
4 ACCPTED 2012-09-07 09:04:28
Your 'template' contains the string % } (right after the 100 there), and python is interpreting that as a formatting instruction.
Double the % percent characters to %% and it'll work.
>>> page = """
... <html>
... <style type="text/css">
... html { height: 100%% }
... body { height: 100%%; margin: 0; padding: 0 }
... #map_canvas { height: 100%% }
... </style>
... %(say)s
... </html>
... """
>>> page % dict(say='foo')
'\n<html>\n <style type="text/css">\n html { height: 100% }\n body { height: 100%; margin: 0; padding: 0 }\n #map_canvas { height: 100% }\n </style>\n foo\n</html>\n '
Alternatively, use the newer .format() method for a format less prone to such problems, although in this specific case that'll get hung up on the { height: 100% } curly braces pairs, so your mileage may very well vary; you'd have to double those instead (so {{ height: 100% }} ).
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