如何在Python中将任意嵌套列表转换为指定格式的字符串？

Absolutely—recursion is perfect for handling arbitrary nested lists like this. Here's a straightforward, reusable function that will flatten any level of nesting, convert all elements to strings, and let you format them into your desired comma-separated string.

Basic Version (For Lists Only) #

This function focuses specifically on lists, which matches your example scenario:

def flatten_nested_list(nested_list):
    for element in nested_list:
        # If the element is another list, recursively flatten it
        if isinstance(element, list):
            yield from flatten_nested_list(element)
        # Otherwise, convert the element to a string and yield it
        else:
            yield str(element)

How to Use It #

Let’s test it with your example code:

b = 15
my_list = [1,2,3,4,[5,6,7,8,[9,["a",b,"c"],10,11]]]

# Flatten the list and join elements with ", "
flat_string = ', '.join(flatten_nested_list(my_list))
print(flat_string)

This will output:
1, 2, 3, 4, 5, 6, 7, 8, 9, a, 15, c, 10, 11

(Note: Your example output included "b" instead of 15, but since b is a variable holding the value 15, the function correctly uses the actual value of the variable when processing the list.)

Enhanced Version (Handles All Iterables Except Strings) #

If you want to support other iterable types (like tuples or sets) without accidentally splitting strings into individual characters, use this expanded version:

from collections.abc import Iterable

def flatten_any_iterable(nested):
    for element in nested:
        # Check if it's an iterable but NOT a string/bytes (to preserve text)
        if isinstance(element, Iterable) and not isinstance(element, (str, bytes)):
            yield from flatten_any_iterable(element)
        else:
            yield str(element)

Why This Works #

Recursion lets us handle unknown nesting depth effortlessly: every time we hit a nested list (or iterable), we dive into it and repeat the process until we reach individual elements. Converting each element to a string ensures everything can be joined into a single, uniform comma-separated string.

This function works no matter how deep your lists are—whether it’s 2 levels or 200.

内容的提问来源于stack exchange，提问作者Saleh Ahmadzada