You can print Unicode objects as well, you don’t need to do str() around it.
Assuming you really want a str:
When you do str(u’\u2013′) you are trying to convert the Unicode string to a 8-bit string. To do this you need to use an encoding, a mapping between Unicode data to 8-bit data. What str() does is that is uses the system default encoding, which under Python 2 is ASCII. ASCII contains only the 127 first code points of Unicode, that is \u0000 to \u007F1. The result is that you get the above error, the ASCII codec just doesn’t know what \u2013 is (it’s a long dash, btw).
You therefore need to specify which encoding you want to use. Common ones are ISO-8859-1, most commonly known as Latin-1, which contains the 256 first code points; UTF-8, which can encode all code-points by using variable length encoding, CP1252 that is common on Windows, and various Chinese and Japanese encodings.
You use them like this:
u'\u2013'.encode('utf8')
The result is a str containing a sequence of bytes that is the uTF8 representation of the character in question:
'\xe2\x80\x93'
And you can print it:
>>> print '\xe2\x80\x93'
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