对嵌套列表进行排序:从排序中排除第一项 [英] Sort nested list: Exclude first item from sorting

问题描述

我有一个csv file，其中包括当前的茶点余额(以逗号分隔，但是在此示例中，删除了逗号,以提高可读性):

I have a csv file which includes the current balance of my refreshments (it is comma separated, but in this example commas , are removed for improved readability):

NAME         AMOUNT         PRICE
Coca-Cola    8              1.25
Fanta        6              1.29
Dr. Pepper   2              2.20
Sprite       10             1.35
Guarana      6              1.80
Pepsi        4              1.25

我将所有数据读入内存(列表)，并使用以下命令进行所有必要的

I read all the data into the memory (list) and do all the necessary editing using:

import csv
# format list for refreshments
items_list = []

with open("my_refresments.csv", newline='') as fileOpener:
    open_csv = csv.reader(fileOpener)
    for rows in open_csv:
        items_list.append(rows)

列表"items_list"现在显示为:

The list 'items_list' now prints out as:

items_list = [["NAME","AMOUNT","PRICE"],
              ["Coca-Cola","8","1.25"],
              ["Fanta","6","1.29"],
              ["Dr. Pepper","2","2.20"],
              ["Sprite","10","1.35"],
              ["Guarana","6","1.80"],
              ["Pepsi","4","1.25"]]

问题

什么给了我这种排序:

QUESTION

What gives me this kind of sorting:

# Notice that this is sorted, but items_list[0] is at it's place

items_list = [["NAME","AMOUNT","PRICE"],
              ["Coca-Cola","8","1.25"],
              ["Fanta","6","1.29"],
              ["Dr. Pepper","2","2.20"],
              ["Sprite","10","1.35"],
              ["Guarana","6","1.80"],
              ["pepsi","4","1.25"]]

除了第一行items_list[0]之外的所有内容都应保持原样，不会被人为误解.

Everything except first row items_list[0] should stay unsorted ergo untouched where it stands.

通常a.sort()是嵌套列表的一个不错的选择，因为它不会对列表中的所有单个项目进行排序，而是对彼此比较的列表进行排序.在这种情况下，我不能使用items_list.sort()，因为它还将在csv文件中包含标头，我想将其保留在它已经位于的位置:items_list[0].这是使用items_list.sort()时发生的情况:

Generally a.sort() is a good option with nested lists because it will not sort all the individual items inside the lists, but instead it sorts the lists compared one to another. In this case I can't use items_list.sort(), because it will include also the headers in csv file, which I want to stay just where it is already located: items_list[0]. Here is what happens when using items_list.sort():

items_list.sort()
[['Coca-Cola', '8', '1.25'],
 ['Fanta', '6', '1.29'], 
 ['Dr. Pepper', '2', '2.20'], 
 ['Sprite', '10', '1.35'], 
 ['Guarana', '6', '1.80'], 
 ['NAME', 'AMOUNT', 'PRICE'], 
 ['Pepsi', '4', '1.25']]

奇怪的是，如果我用lower case编写所有的茶点，那会起作用，因为TEXT > text，但是我不想这样做.我想使用slice排除第一行(标题)，但是它似乎并没有任何效果(或者也许我做错了):

Strangely, if I write all the refreshments with lower case, it will work, because TEXT > text, but I don't want to do that. I would like to use slice to exclude the first row (headers), but it doesn't seem to have any effect what so ever (or maybe I'm doing it wrong):

# This doesn't do anything
items_list[1:].sort()

一种可能的解决方案

我能做的是

One possible solution

What I could do is to

1. 首先以一种或另一种方式将标头复制到另一个列表中temp_list = [items_list[0]]
2. 使用del items_list[0]语句删除items_list[0]
3. 使用items_list.sort()对列表进行排序，最后
4. 使用items_list.insert(0, temp_list)
将标头插入已排序列表的index(0)

1. first copy headers into another list in one way or another temp_list = [items_list[0]]
2. delete items_list[0] using the del items_list[0] statement
3. sort the list using items_list.sort(), and finally
4. insert headers into the sorted list's index(0) with items_list.insert(0, temp_list)

像这样:

def sort_csv_list_exclude_headers(file_name):

    items_list = []

    with open(file_name, newline='') as fileOpener:
        open_csv = csv.reader(fileOpener)
        for rows in open_csv:
            items_list.append(rows)

    temp_list = [items_list[0]]
    del items_list[0]
    items_list.sort()
    items_list.insert(0, temp_list[0])

    with open(file_name, "w") as fileWriter:
        write_csv = csv.writer(fileWriter, lineterminator='\n')
        write_csv.writerows(items_list)

sort_csv_list_exclude_headers("SODA_BALANCE.csv")

实际上，当将csv与超过1000000行的刷新"一起使用时，这通常是非常好的和简单的.

Actually this is pretty good and simple in general when using csv with > 1 000 000 rows of "refreshments".

还有其他(更简单的)方法吗?

Is there any other (more simple) method?

推荐答案

一个干净的衬里将是:

items_list[1:] = sorted(items_list[1:])

引用: https://stackoverflow.com/a/5827649/937153

这篇关于对嵌套列表进行排序:从排序中排除第一项的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！