How do I convert unicode characters to floats in Python?

Question

I am parsing a webpage which has Unicode representations of fractions. I would like to be able to take those strings directly and convert them to floats. For example:

"⅕" would become 0.2

Any suggestions of how to do this in Python?

Answer 1

Since there are only a fixed number of fractions defined in Unicode, a dictionary seems appropriate:

Fractions = {
    u'¼': 0.25,
    u'½': 0.5,
    u'¾': 0.75,
    u'⅕': 0.2,
    # add any other fractions here
}

Update: the unicodedata module is a much better solution.

Answer 2

You want to use the unicodedata module:

import unicodedata
unicodedata.numeric(u'⅕')

This will print:

0.20000000000000001

If the character does not have a numeric value, then unicodedata.numeric(unichr[, default]) will return default, or if default is not given will raise ValueError.

Answer 3

Maybe you could decompose the fraction using the "unicodedata" module and then look for the FRACTION SLASH character and then it's just a matter of simple division.

For example:

>>> import unicodedata
>>> unicodedata.lookup('VULGAR FRACTION ONE QUARTER')
u'\xbc'
>>> unicodedata.decomposition(unicodedata.lookup('VULGAR FRACTION ONE QUARTER'))
'<fraction> 0031 2044 0034'

Update: I'll leave this answer here for reference but using unicodedata.numeric() as per Karl's answer is a much better idea.

Answer 4

In Python 3.1, you don't need the 'u', and it will produce 0.2 instead of 0.20000000000000001 .

>>> unicodedata.numeric('⅕')
0.2