創建一個二維列表

Question

我需要一個二維列表來存儲關於學生及其成績的信息。

當我運行我的程序時，我只是得到一個數字列表，但我需要爲每個學生單獨列出。誰能幫我？

這是我迄今所做的：

COLS= int(input("number of students to enter ")) 
ROWS= int(input("number of grades per student ")) 

def main(): 
    number =[] 


    for c in range(COLS): 
     student =(input("enter student ID number ")) 
     number.append(student) 

     for r in range (ROWS): 
      grades =(input("Enter grade for module: ")) 
      number.append(grades) 

    print(number) 

my result is 
number of students to enter 2 
number of grades per student 4 
enter student ID number 1234 
Enter grade for module: 55 
Enter grade for module: 66 
Enter grade for module: 43 
Enter grade for module: 33 
enter student ID number 2345 
Enter grade for module: 34 
Enter grade for module: 56 
Enter grade for module: 78 
Enter grade for module: 99 
['1234', '55', '66', '43', '33', '2345', '34', '56', '78', '99'] 
>>> 

Answer 1

你需要創建一個新的名單每一行：

for c in range(COLS): 
    grades = [] 
    student =(input("enter student ID number ")) 
    number.append(student) 
    number.append(grades) 

    for r in range (ROWS): 
     grade =(input("Enter grade for module: ")) 
     grades.append(grade) 

Answer 2

你將其插入之前就建立一個列表number列表：

for c in range(COLS): 
    student =(input("enter student ID number ")) 
    temp_arr = [student] # make a temporary array for the student id and their grades 

    for r in range (ROWS): 
     grades =(input("Enter grade for module: ")) 
     temp.append(grades) # append to the temp array here 

    # after you are done getting the grades 
    # insert the entire temp array into the number array 
    number.append(temp) 

此外，這些數據可能如果你製作了一個類Student，它可以有一個id和一個grades的列表存儲在一個更好的方式。

Answer 3

我會用通過學生證指數的字典：

COLS= int(input("number of students to enter ")) 
ROWS= int(input("number of grades per student ")) 

def main(): 
    student_grades = {} 

    for c in range(COLS): 
     student =(input("enter student ID number ")) 
     grades = [] 

     for r in range (ROWS): 
      grade =(input("Enter grade for module: ")) 
      grades.append(grade) 
     student_grades[student] = grades 

Answer 4

按我的意見，用list & dict comprehensions這樣的例子：

cols = int(input("Number of students: ")) 
rows = int(input("Number of grades per student: ")) 

grades = {input("Enter student ID number: "): 
      [input("Enter grade for module: ") for _ in range(rows)] 
      for _ in range(cols)} 

注意這是一本字典爲Kyle Strand's answer，而不是一個列表。這更適合數據，並且稍後會使它更容易處理。

rows = int(input("Number of grades per student: ")) 

def get_students(): 
    while True: 
     value = input("Enter student ID number, or nothing to finish: ") 
     if not vale: 
      return 
     else: 
      yield value 

grades = {student: [input("Enter grade for module: ") for _ in range(rows)] 
      for student in get_students()} 

這裏是這樣的：

至於另注，更好的接口可以通過重複，直到用戶決定不進入更多的學生，而不是要求的先期多少學生將進入實現用發生器實現，這會產生從用戶獲得的新學生號碼，直到用戶什麼都不輸入。

Answer 5

我認爲最好使用列表的字典而不是二維列表 - 列表的列表 - 因爲它使訪問輸入和訪問的數據更容易和可讀。出於同樣的原因，我還將代碼中的名稱從number更改爲grades，以更好地反映所投入的內容。輸入您的樣本數據後

COLS = int(input("number of students: ")) 
ROWS = int(input("number of grades per student: ")) 

grades = {} 

def main(): 
    for c in range(COLS): 
     student = int(input("enter student ID: ")) 
     grades[student] = [] # initialize to empty row of grades 

     for r in range(ROWS): 
      grade = int(input("Enter grade for module: ")) 
      grades[student].append(grade) 

    for student in grades.keys(): 
     print 'student:{}, grades:{}'.format(student, grades[student]) 

輸出：

student:2345, grades:[34, 56, 78, 99] 
student:1234, grades:[55, 66, 43, 33]