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

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 2

Those Unicode representations of floats are called Vulgar Fractions

You can covert them to floats using unicodedata.numeric(char)

However, numeric(char) won't work on something like 3¾. That takes a bit more effort:

from unicodedata import numeric

samples = ["3¼","19¼","3 ¼","10"]

for i in samples:
    if len(i) == 1:
        v = numeric(i)
    elif i[-1].isdigit():
        # normal number, ending in [0-9]
        v = float(i)
    else:
        # Assume the last character is a vulgar fraction
        v = float(i[:-1]) + numeric(i[-1])
    print(i, v)

Output:

3¼ 3.25
19¼ 19.25
3 ¼ 3.25
10 10.0

You might also be interested isolating these vulgar fractions from broader user input using regular expressions. You can do so using ranges of their unicode character codes:

/[\u2150-\u215E\u00BC-\u00BE]/g

Sample: https://regexr.com/3p8nd