Python sorted() 函数无法正常工作 [英] Python sorted() function not working the way it should

问题描述

基本上我有一个嵌套列表，我试图对第一个索引进行排序我复制了 python howto 说的方法，但它似乎不起作用，我不明白为什么:

来自网站的代码:

<预><代码>>>>student_tuples = [('约翰', 'A', 15),('简', 'B', 12),('戴夫', 'B', 10),]>>>sorted(student_tuples, key=lambda student: student[2]) # 按年龄排序[('dave', 'B', 10), ('jane', 'B', 12), ('john', 'A', 15)]

我的代码:

def print_scores(self):尝试:#打开txt并读取数据，然后将数据分成以-"分隔的列表f = open(appdata + "scores.txt", "r")fo = f.read()f.close()用户列表 = fo.split('
')sheet_list = []对于用户列表中的用户:sheet = user.split('-')如果 len(sheet) != 2:继续sheet_list.append(sheet)sorted(sheet_list, key = lambda ele : ele[1]) #这里是复制的部分！如果 len(sheet_list) >20: # 只打印前 20 个分数sheet_list = sheet_list[len(sheet_list) - 21 :len(sheet_list) - 1]#在漂亮的表格中打印分数打印姓名分数"对于 sheet_list 中的用户:尝试:名称 = 用户 [0]分数 = 用户 [1]大小 = len(名称)对于范围内的 x(0,14):如果 x >尺寸 - 1:sys.stdout.write(" ")别的:sys.stdout.write(name[x])sys.stdout.write(score + "
")除了:打印 ""除了:打印没有要显示的分数！"

问题是打印出来的列表和txt里的一模一样，好像排序功能什么都没做！

示例:

txt 文件中的数据:

Jerry-1284汤姆-264巴里-205omgwtfbbqhaxomgsss-209长颈鹿-1227

打印的内容:

名称分数杰瑞 1284汤姆 264巴里 205omgstfbbqhaxom209长颈鹿 1227

解决方案

sorted 返回一个新列表.如果要修改现有列表，请使用

sheet_list.sort(key = lambda ele : ele[1])

Basically I have a nested list that I am trying to sort through the 1'st index I copied the way that the python howto says how to do it but it doesn't seem to work and I don't understand why:

code from the website:

>>> student_tuples = [
    ('john', 'A', 15),
    ('jane', 'B', 12),
    ('dave', 'B', 10),
    ]
>>> sorted(student_tuples, key=lambda student: student[2])   # sort by age
    [('dave', 'B', 10), ('jane', 'B', 12), ('john', 'A', 15)]

My code:

def print_scores(self):
    try:
        #opening txt and reading data then breaking data into list separated by "-"
        f = open(appdata + "scores.txt", "r")
        fo = f.read()
        f.close()
        userlist = fo.split('
')
        sheet_list = []
        for user in userlist:
            sheet = user.split('-')
            if len(sheet) != 2:
                continue
            sheet_list.append(sheet)
        sorted(sheet_list, key = lambda ele : ele[1]) #HERE IS THE COPIED PART!
        if len(sheet_list) > 20: # only top 20 scores are printed
            sheet_list = sheet_list[len(sheet_list) - 21 :len(sheet_list) - 1]
       #prints scores in a nice table
        print "name          score"
        for user in sheet_list:
            try:
                name = user[0]
                score = user[1]
                size = len(name)
                for x in range(0,14):
                    if x > size - 1:
                        sys.stdout.write(" ")
                    else:
                        sys.stdout.write(name[x])
                sys.stdout.write(score + "
")
            except:
                print ""


    except:
         print "no scores to be displayed!"

The bug is that the resulting printed list is exactly like how it was in the txt as if the sorting function didn't do anything!

Example:

Data in txt file:

Jerry-1284
Tom-264
Barry-205
omgwtfbbqhaxomgsss-209
Giraffe-1227

What's printed:

Name          Score
Jerry         1284
Tom           264
Barry         205
omgstfbbqhaxom209
Giraffe       1227

解决方案

sorted returns a new list. If you want to modify the existing list, use

sheet_list.sort(key = lambda ele : ele[1])

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