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Python

Iain Watson
Iain Watson
3,031 Points
Posted by Iain Watson
Iain Watson
3,031 Points

morse.py

In each iteration I'm adding "dot" or "dash" to a list. So why does "-".join() put dashes between the letters rather than the words?

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

    def __str__(self):
        morse = []
        for p in self.pattern:
            if p == ".":
                p = "dot"
                morse += p
            elif p == "_":
                p = "dash"
                morse += p
        return "-".join(morse)


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

1 Answer

Ryan S
Ryan S
27,276 Points
Ryan S
Ryan S
27,276 Points

Hi Iain,

The issue isn't with the join method, it is actually with the way you are adding items to your morse list. Notice you are using addition assignment (+=). This is actually shorthand for the .extend() method on a list. So it will take all letters in the string and add them individually:

>>> morse = []
>>> p = "dot"
>>> morse += p
>>> morse
['d', 'o', 't']

To add a full string as an item, you need to use append():

>>> morse = []
>>> p = "dot"
>>> morse.append(p)
>>> morse
['dot']