Python 2：AttributeError：“模块”对象没有属性“扫描”

Question

I'm currently learning Python with the book "Learn python the hard way" and I'm getting an error.

I have a folder called ex48 where a lexicon.py is located. In this lexicon.py I have 'scan' function, which gets one input, splits it and identifies the words, then returns a list.:

def scan(self, input):
    identifiedWords = []
    words = input.split(" ")
    for i in len(words):
        # check if it's a number first
        try:
            identifiedWords[i] = ('number', int(words[i]))
        except ValueError:
            # directions
            if words[i].lower() == 'north':
                identifiedWords[i] = ('direction', 'north')
            elif words[i].lower() == 'east':
                identifiedWords[i] = ('direction', 'east')

...

            # error
            else:
            identifiedWords[i] = ('error', words[i])

    return identifiedWords

Outside of my ex48 folder I'm trying to use this function in powershell. I'm doing:

>>> from ex48 import lexicon
>>> lexicon.scan("north south")
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
AttributeError: 'module' object has no attribute 'scan'
>>>

The function should return [('direction', 'north'), ('direction', 'south')

Am I doing something wrong with the import or is the syntax of the scan function wrong?

Answer 1

To mark ex48 as a Python module, you have to create an empty file called __init__.py Also, the scan method contains the argument "self", which makes it a class method. You have to initialize the class before using the method.

Edit: I see, you have a class called Lexicon inside the module called lexicon . You have to first init your class and then call the function:

from ex48 import lexicon
lex = lexicon.Lexicon()
lex.scan("north south")

Answer 2

Wrong usage of self is whats giving you the problem : https://pythontips.com/2013/08/07/the-self-variable-in-python-explained/

def scan(input):
    ....

should solve it. The link is to understand why.