So I am working with recursion,
The problem is:
" Good(43) Morning"
I have to use recursion to print all the information inside parenthesis like this: "(43)"
My code so far is:
def extractor(myString):
if len(myString) == 0:
return ""
if myString[0] == "(":
return myString[0]
if myString[0] == ")":
return myString[:]
else:
return extractor(myString[1:])
I can only get parenthesis. How could I change it?
You're almost there:
def extractor(myString):
if not myString: # empty strings are falsy
return ""
if myString[0] == "(":
if myString[-1] == ")": # success
return myString
else: # only starts with (, trim from the end
return extractor(myString[:-1])
else: # doesn't start with (, trim from beginning
return extractor(myString[1:])
str.startswith and str.endswith are methods, not functions, but fair enough, I'll change it.
If you are interested, here is an iterative version of your code. :)
def iterative_extractor(mystring):
if not mystring:
return ""
while mystring[0] != "(" or mystring[-1] != ")":
if mystring[0] != "(":
mystring = mystring[1:]
else:
mystring = mystring[:-1]
return mystring
OR:
def iterative_extractor(mystring):
if not mystring:
return ""
while mystring[0] != "(":
mystring = mystring[1:]
while mystring[-1] != ")":
mystring = mystring[:-1]
return mystring
Output:
mystring = "Lol (234) mate!"
print(iterative_extractor(mystring))
>>> "(234)"
