Expand currency sign with moving words inside string

Question

How can I achieve this without using if operator and huge multiline constructions?

Example:

around $98 million last week
above $10 million next month
about €5 billion past year
after £1 billion this day

Convert to

around 98 million dollars last week
above 10 million dollars next month
about 5 billion euros past year
after 1 billion pounds this day

Answer 1

You probably have more cases than this so the regular expression may be too specific if you have more cases, but re.sub can be used with a function to process each match and make the correct replacement. Below solves for the cases provided:

import re

text = '''\
around $98 million last week
above $10 million next month
about €5 billion past year
after £1 billion this day
'''

currency_name = {'$':'dollars', '€':'euros', '£':'pounds'}

def replacement(match):
    # group 2 is the digits and million/billon,
    # tack on the currency type afterward using a lookup dictionary
    return f'{match.group(2)} {currency_name[match.group(1)]}'

# capture the symbol followed by digits and million/billion
print(re.sub(r'([$€£])(\d+ [mb]illion)\b', replacement, text))

Output:

around 98 million dollars last week
above 10 million dollars next month
about 5 billion euros past year
after 1 billion pounds this day