1.



import re


replace_values = ['one', 'two', 'three']
replace_keys = [str(i) for i in xrange(1, 4)]
replace_dict = dict(zip(replace_keys, replace_values))

def replace(match):
return replace_dict[match.group(0)]


string = '1 adfa fa 2 fafsa 3 adfaf'
print re.sub(r'(^|\b)[1-3]($|\b)', replace, string)