头歌实践教学平台Python-列表类型翻转教学

第1关 输入数据创建列表

score_ls = []
for i in range(10):
    a = float(input())
    score_ls.append(a)  
print(score_ls)

第2关 计算每位选手的成绩

score_ls = []
for i in range(10):
    a = float(input())
    score_ls.append(a)
print(score_ls)
print(f'最高分{max(score_ls):.3f},最低分{min(score_ls):.3f},平均分{sum(score_ls) / len(score_ls):.3f}')

第3关 去除一个最高分和一个最低分

score_ls = []
for i in range(10):
    a = float(input())
    score_ls.append(a)  
print(score_ls)
score_ls.remove(max(score_ls))
score_ls.remove(min(score_ls))
print(score_ls)
print(f'最高分{max(score_ls):.3f},最低分{min(score_ls):.3f},平均分{sum(score_ls) / len(score_ls):.3f}')

第4关 计算中位数成绩

score_ls = []
for i in range(10):
    a = float(input())
    score_ls.append(a)  
print(score_ls)
score_ls.remove(max(score_ls))
score_ls.remove(min(score_ls))
score_ls.sort() 
print(score_ls)
print(f'去掉最高分和最低分后，中位数成绩为：{(score_ls[len(score_ls)//2]+score_ls[len(score_ls)//2-1])/2:.3f}')

第5关 去除弃权评委成绩

score_ls = []
for i in range(10):
    a = input()
    score_ls.append(a) 
print(score_ls)
while '' in score_ls:
        score_ls.remove('')
print(score_ls)
score_ls = list(map(float, score_ls))
score_ls.remove(max(score_ls))
score_ls.remove(min(score_ls))
print(score_ls) 
print(f'{max(score_ls):.3f}, {min(score_ls):.3f}, {sum(score_ls) / len(score_ls):.3f}')
 

第6关 将平均成绩附加到列表末尾

score_ls = []
for i in range(10):
    a = input()
    score_ls.append(a) 
print(score_ls)
while '' in score_ls:
        score_ls.remove('')
score = list(map(str, score_ls))
score_ls = list(map(float, score_ls))
score_ls.remove(max(score_ls))
score_ls.remove(min(score_ls))
avg_score = sum(map(float, score_ls))/len(score_ls) 
score.append(str(round(avg_score, 2)))
print(score) 

第7关 读文件到二维列表

def file_to_lst(file,n):
    list1 = []
    with open(file) as fr:  
        for i in range(n):
            score_ls = fr.readline().strip()
            score_ls = score_ls.split(',')
            list1.append(score_ls)
        print(list1)
            
if __name__ == '__main__':
    filename = '/data/bigfiles/mark_score.csv'
    n = int(input())
    file_to_lst(filename,n)

第8关 二维列表数据分析

def file_to_lst(file, n):
    """将文件名变量file指向的文件中的用逗号分隔的数据转为二维列表"""
    list1 = []
    with open(file) as fr:  # 创建文件对象
        for i in range(n):
            score_ls = fr.readline().strip()
            score_ls = score_ls.split(',')
            list1.append(score_ls)
        return list1    
 
if __name__ == '__main__':
    filename = '/data/bigfiles/mark_score.csv'
    n = int(input())
    list2=[]
    for lst in file_to_lst(filename, n):  # 遍历二维列表，lst为子列表
        while '' in lst:  # 循环判定子列表中是否还有空字符串
            lst.remove('')  # 移除子列表中的空字符串
        lst = list(map(float, lst))  # 当前子列表转浮点数
        lst.remove(max(lst))
        lst.remove(min(lst))
        avg_score = sum(map(float, lst))/len(lst) 
        lst.append(float(round(avg_score, 2)))
        list2.append(lst)
    print(list2)

第9关 成绩排序

def file_to_lst(file):
    with open(file) as fr:
        score_ls = [line.strip().split(',') for line in fr]
    return score_ls
 
def del_null_string(score_ls):
    score_ls_float = []
    for lst in score_ls:
        while '' in lst:
            lst.remove('')
        lst = list(map(float,lst))
        score_ls_float.append(lst)
    return score_ls_float
 
def add_avg(score_ls_float):
    for i in range(len(score_ls_float)):
        score_ls_float[i].remove(max(score_ls_float[i]))
        score_ls_float[i].remove(min(score_ls_float[i]))
        avg = sum(score_ls_float[i]) / len(score_ls_float[i])
        score_ls_float[i].append(round(avg,2))
    return score_ls_float
 
if __name__ == '__main__':
    filename = '/data/bigfiles/mark_score.csv'
    n = int(input())
    score_lst = file_to_lst(filename)
    score_lst_f = del_null_string(score_lst)
    score_avg = add_avg(score_lst_f)
    print(sorted(score_avg, key=lambda x: (x[-1],-x[-2]),reverse=True)[:n])