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returning the right pattern

I thought they wanted me to return ("-" "."), but not sure why I keep getting "didn't get the right pattern" error

class Letter:
    def __init__(self, pattern=None):
        self.pattern = pattern

    def __iter__(self):
        yield from self.pattern

    def __str__(self):
        output = []
        for blip in self:
            if blip == '.':
        return '-'.join(output)

    def from_string(cls, pattern):
        fix_me =Letter("-" ".")
        return fix_me

class S(Letter):
    def __init__(self):
         pattern = ['.', '.', '.']

3 Answers

Chris Freeman
Chris Freeman
Treehouse Moderator 68,390 Points

The __str__ method uses the list of “.” and “_” stored in self.pattern to create a string of “dot” and “dash”.

The challenge is looking for the opposite. A from_string class method that takes any string containing “dot”s and “dash”s, splits it up and converts it into a list of “.” and “_”, then uses that is to create an instance of Letter.

A for loop works well for this.

Post back if you need more help. Good luck!!!

Hi Chris , I tried to convert it into the requested value like thus:

@classmethod   # declaring class method
def from_string(cls, pattern):  # a from_string class that takes any string containing "dot" and "dash"
      fix_me = Letter([".", "_"])   # Splits it up and convert it into a list , then create the instance
      return fix_me   # return the value requested.

I followed the steps you mentioned above but , i'm still getting "try again" errors. Also i would like to know how to use a for loop for this challenge, although i think i am kind of close with the above solution.

[MOD: added ```python formatting -cf]

Chris Freeman
Chris Freeman
Treehouse Moderator 68,390 Points

Your current solution does not use the value passed into the parameter pattern. You'll need a for loop that splits pattern changing any "dot"s and "dash"es to "." and "_".

Chris Freeman
Chris Freeman
Treehouse Moderator 68,390 Points

You are close. They are looking for an underscore ("_")

Hello Chris , I tried the underscore, but I still get the error "didn't get the right pattern"

I just did