CODEWITHSUNDEEP
pythonpython-3.x
AndSolomin34
AndSolomin34

Reputation: 409

access list in a 2x-nested function

def get_html(url):
    response = urllib.request.urlopen(url)
    return response.read()


def parse_main(html):
    webpage = BeautifulSoup(html, features="html.parser")
    table = webpage.find('table', id='itemList')

    for a_tag in table.find_all('a', class_='all'):
        parse_movie(get_html('https://www.somerandommovieswebsite.com' + a_tag['href']))


def parse_movie(html):
    web_page = BeautifulSoup(html, features="html.parser")
    info = web_page.find('h1', class_="moviename")
    movies.append(info.text)


def main():
    movies = []
    parse_main(get_html('https://www.somerandommovieswebsite.com'))
    print(movies)


if __name__ == '__main__':
    main()

How do I access the movies list (that is defined in main() function) in parse_movie which is nested in parse_main. Can't append anything to the list because of "unresolved referrence 'movies'" error. Using nonlocal didn't help

Upvotes: 1

Views: 81

Answers (5)

Syed Qasim Ahmed
Syed Qasim Ahmed

Reputation: 1362

There are several ways to do it.

First define globally movies.

Second you can just pass a list as a parameter like that.

Since lists are passed by reference and we are appending the list which is define in main function and we don't need to return to the main function.

def parse_main(html,movies):
    webpage = BeautifulSoup(html, features="html.parser")
    table = webpage.find('table', id='itemList')

    for a_tag in table.find_all('a', class_='all'):
        parse_movie(get_html('https://www.somerandommovieswebsite.com' + a_tag['href']),movies)


def parse_movie(html,movies):
    web_page = BeautifulSoup(html, features="html.parser")
    info = web_page.find('h1', class_="moviename")
    movies.append(info.text)


def main():
    movies = []
    parse_main(get_html('https://www.somerandommovieswebsite.com'),movies)
    print(movies)

Third approach is to make a list inside a function and return it

def parse_main(html):
    webpage = BeautifulSoup(html, features="html.parser")
    table = webpage.find('table', id='itemList')
    movies = []
    
    for a_tag in table.find_all('a', class_='all'):
        movies.append (parse_movie(get_html('https://www.somerandommovieswebsite.com' + a_tag['href'])))
    return movies
    
def parse_movie(html):
    web_page = BeautifulSoup(html, features="html.parser")
    info = web_page.find('h1', class_="moviename")
    return info.text

def main():
    movies = parse_main(get_html('https://www.somerandommovieswebsite.com'))
    print(movies)

Upvotes: 4

Plopp
Plopp

Reputation: 977

Pass the movies list as an argument and avoid using global variables, in most cases it's better.

The issue was that movies was a local variable inside ̀parse_movie, meaning it's a different variable than the one defined in your main.

I simply passed the ̀movies variable from the main function down to the parse_movie one and added return statements.

def get_html(url):
    response = urllib.request.urlopen(url)
    return response.read()


def parse_main(html):
    movies = []
    webpage = BeautifulSoup(html, features="html.parser")
    table = webpage.find('table', id='itemList')

    for a_tag in table.find_all('a', class_='all'):
        movies.append(parse_movie(get_html('https://www.somerandommovieswebsite.com' + a_tag['href'])))
    return movies


def parse_movie(html):
    web_page = BeautifulSoup(html, features="html.parser")
    info = web_page.find('h1', class_="moviename")
    return info.text


def main():
    movies = parse_main(get_html('https://www.somerandommovieswebsite.com'))
    print(movies)


if __name__ == '__main__':
    main()

Upvotes: 1

Ashish
Ashish

Reputation: 4330

The easiest approach would be using a global variable. But you should avoid using global variables whenever possible. You can change your code something like this and avoid using global variables and passing the variable as parameter.

def get_html(url):
    response = urllib.request.urlopen(url)
    return response.read()


def parse_main(html):
    parse_movies = []
    webpage = BeautifulSoup(html, features="html.parser")
    table = webpage.find('table', id='itemList')

    for a_tag in table.find_all('a', class_='all'):
        parse_movies.append(parse_movie(get_html('https://www.somerandommovieswebsite.com' + a_tag['href'])))
    return movies


def parse_movie(html):
    web_page = BeautifulSoup(html, features="html.parser")
    info = web_page.find('h1', class_="moviename")
    return info.text


def main():
    movies = parse_main(get_html('https://www.somerandommovieswebsite.com'))
    print(movies)


if __name__ == '__main__':
    main()

Upvotes: 1

L3viathan
L3viathan

Reputation: 27283

I think you should neither use a global variable here nor pass it as an argument:

def get_html(url):
    response = urllib.request.urlopen(url)
    return response.read()


def parse_main(html):
    movies = []
    webpage = BeautifulSoup(html, features="html.parser")
    table = webpage.find('table', id='itemList')

    for a_tag in table.find_all('a', class_='all'):
        movies.append(
            parse_movie(get_html('https://www.somerandommovieswebsite.com' + a_tag['href']))
        )
    return movies


def parse_movie(html):
    web_page = BeautifulSoup(html, features="html.parser")
    info = web_page.find('h1', class_="moviename")
    return info.text


def main():
    movies = parse_main(get_html('https://www.somerandommovieswebsite.com'))
    print(movies)


if __name__ == '__main__':
    main()

Upvotes: 4

Reda Drissi
Reda Drissi

Reputation: 1672

movies is a local variable inside your main function, so it's normal your function doesn't find it, either make it global (not always a good idea) or pass it as an argument.

Upvotes: 0

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