python-3.x - 列表理解和打印功能(List Comprehension and print function)

Question

I'm trying to write a code in Python 3.x using list comprehension.

(我正在尝试使用列表理解在Python 3.x中编写代码。)

My code should print letters out of a list and remove duplication.

(我的代码应从列表中打印字母并删除重复项。)

print(list(set(([letter_list.append(letter) for word in word_list for letter in word]))))

The code runs with no traceback errors but the output is [None]

(该代码运行无回溯错误，但输出为[None])

  ask by MoSiraj translate from so

Answer 1

The append method modifies an (existing) list in place and returns None.

(append方法修改一个（现有）列表，并返回None。)

A list comprehension creates a new list by itself, so you don't need appending here.

(列表理解本身会创建一个新列表，因此您无需在此处追加。)

Try this:

(尝试这个：)

print(list(set(([letter for word in word_list for letter in word]))))