# Question 7: Find and Replace
# For this question you need to define two procedures:
# make_converter(match, replacement)
# Takes as input two strings and returns a converter. It doesn't have
# to make a specific type of thing. It can
# return anything you would find useful in apply_converter.
# apply_converter(converter, string)
# Takes as input a converter (produced by make_converter), and
# a string, and returns the result of applying the converter to the
# input string. This replaces all occurrences of the match used to
# build the converter, with the replacement. It keeps doing
# replacements until there are no more opportunities for replacements.
def make_converter(match, replacement):
convert = [match, replacement]
return convert
def apply_converter(converter, string):
start = string.find(converter[0])
# print start
if start != -1:
end = start + len(converter[0])
string = string[:start] + converter[1] + string[end:]
# print string
return apply_converter(converter, string)
return string
# For example,
c1 = make_converter('aa', 'a')
print apply_converter(c1, 'aaaa')
#>>> a
c = make_converter('aba', 'b')
print apply_converter(c, 'aaaaaabaaaaa')
#>>> ab
# Note that this process is not guaranteed to terminate for all inputs
# (for example, apply_converter(make_converter('a', 'aa'), 'a') would
# run forever).