将列表转换为不带"join"的字符串 [英] Convert a list to a string without 'join'

问题描述

我正在尝试创建自己的函数，该函数将字符列表转换为字符串.我不允许使用加入".我需要使用循环来执行此操作.我认为我有正确的基础，但是我不确定如何正确地将其实现到功能中.我是编程新手.

I'm trying to create my own function that converts a list of characters into a string. I'm not allowed to use 'join'. I need to use a loop to do this. I think I have the basis of it right, but I'm not really sure how to implement it into the function properly. I'm new to programming.

这是我正在使用的代码:

Here's the code I'm using:

def to_string(my_list):

    # This line will eventually be removed - used for development purposes only.
    print("In function to_string()")

    # Display letters in a single line 
    for i in range(len(my_list)):
        print(my_list[i], end='') 

        # Separate current letter from the next letter 
        if i<(len(my_list))-1: 
            print(", ", end='')

    # Returns the result
    return ('List is:', my_list)

返回我想要的结果(如果列表为['a'，'b'，'c']，则返回a，b，c).但是我们有一个测试文件"用来运行包含以下代码的函数:

That returns the result I want (if the list is ['a', 'b', 'c'] it returns a, b, c). But there's a 'test file' we're meant to use to run the function which contains this code:

print("\nto_string Test")
string = list_function.to_string(str_list1)
print(string)
print(list_function.to_string(empty))

它给出了这个结果:

to_string Test
In function to_string()
r, i, n, g, i, n, g('List is:', ['r', 'i', 'n', 'g', 'i', 'n', 'g'])
In function to_string()
('List is:', [])

这似乎表明我完全搞砸了，这与我认为的打印"功能有关.谁能告诉我我要去哪里错了?

Which seems to indicate that I messed up entirely, something to do with the 'print' function I think. Can anyone please tell me where I'm going wrong?

推荐答案

您的函数打印您的字符串到 stdout ，然后返回列表本身不变.

Your function prints your string to stdout, then returns the list itself unchanged.

构建一个字符串并返回它而不是打印:

Build a string and return that instead of printing:

def to_string(my_list):
    result = ''
    last = len(my_list) - 1
    for pos, elem in enumerate(my_list):
        result += str(elem)
        if pos != last:
            result += ', '
    return result

这会遍历所有元素，并与 枚举保持位置相对()函数;这样，很容易检测是否将最后一个元素添加到结果中.

This loops over all elements, keeping a position counter with the enumerate() function; this way it's easy to detect if we are adding the last element to the result.

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