使用生成器/列表推导获得此输出？

Question

I'm having a bit of trouble with something, and I don't know how I could do it.

Well, I'm creating a dynamic form with buttons that adapts to how many files (in this case, movies) there are in a directory.

I have got this so far:

path="C:\\Users\\User\\Desktop\\test\\"  # insert the path to the directory of interest
movies = []
dirList=os.listdir(path)

for fname in dirList: # loops through directory specified
    print fname # prints file name
    movies.append(fname) # adds the file name to list

my_form = form.Form([form.Button("btn", id="btn" + movies[i], value = i, html=movies[i], class_="btn" +movies[i]) for i in range(len(movies))]) 

However, I want the list comprehension/generator to make my_form look something like this:

my_form = form.Form(
    form.Button("btn", id="btnA", value="A", html="Movie1", class_="btnA")
    form.Button("btn", id="btnB", value="B", html="Movie2", class_="btnB")
)

As you can see instead of the movie name being the id, it is btnA or btnB .

So how could I generate that output?

Answer 1

I think you want to do something like:

from string import ascii_uppercase

buttons = [form.Button("btn", id="btn{0}".format(char), value=char, 
                       html=movie, class_="btn{0}".format(char))
           for char, movie in zip(ascii_uppercase, movies)]

my_form = form.Form(buttons)

This uses the letters in string.ascii_uppercase to label each item in movies .

Answer 2

If I understand correctly, you want the id to be btn + a letter according to the index of the movie?

you can use this code:

def letterForIndex(idx):
    return chr(ord('A')+idx)

so you would do :

 my_form = form.Form([form.Button("btn", id="btn" + letterForIndex(i),
 value = letterForIndex(i), html=movies[i], class_="btn" +letterForIndex(i)) for i in range(len(movies))])