Question

所以我有这个代码，以便我可以将一些学生添加到列表中，但我也有一行，如果他们输入一个空白字符串，它会将用户带回菜单。但是，当我输入空白字符串时，它还会将其添加到学生列表中。我怎么能改变它？

students = []

ans = True
while ans:
    print ("""
a.Add new students
b.Show student list
c.Delete a student
d.Exit
""")
ans = input("What would you like to do? ") 

if ans == "a": 
  enterStudent = input ("Enter a new student name:")
  students = [enterStudent]
  while enterStudent != "": #loop to enter multiple student names
      enterStudent = input ("Enter a new student name:")
      students.append (enterStudent)
      print ("The list now contains the students :",students)
elif ans == "b":
    print("\n The current student list is:")
    print (*students,sep='\n')
elif ans == "c": #delete a student from the list.
    removeStudent = input ("Enter a student name to delete:") 
    students.remove (removeStudent)
elif ans == "d":
    print("\n Goodbye")
elif ans != "":
    print("\n Try again")

输出：

 What would you like to do? a
 Enter a new student name:Bob Bob
 Enter a new student name:Bob Bob
 The list now contains the students : ['Bob Bob', 'Bob Bob']
 Enter a new student name:
 The list now contains the students : ['Bob Bob', 'Bob Bob', '']

我遇到的另一个问题是，在输入两个学生名字后，它会在用户输入空白字符串之前打印出列表。

我该如何解决这个问题？感谢。

Answer 1

你的循环没有测试学生名称是否为空，直到它回到循环的顶部，这是在它添加条目列表之后。尝试：

students = []
while True:
    enterStudent = input("Enter a new student name:")
    if not enterStudent:
        break
    students.append(enterStudent)
    print ("The list now contains the students :",students)

Answer 2

你应该添加一行来检查包含学生姓名的行是否为空白，在这种情况下，通过退出while循环返回菜单

此外，您第一次要求学生姓名实际上并未使用。我会删除while上面的两行，而只是为enterStudent指定一个非空值。所以我会改变这个：

  enterStudent = input ("Enter a new student name:")
  students = [enterStudent]
  while enterStudent != "": #loop to enter multiple student names
      enterStudent = input ("Enter a new student name:")
      students.append (enterStudent)
      print ("The list now contains the students :",students)

对此：

  students = []
  enterStudent = "goIntoWhile"
  while enterStudent != "": #loop to enter multiple student names
      enterStudent = input ("Enter a new student name:")
      if enterStudent == "":
          break
      students.append (enterStudent)
      print ("The list now contains the students :",students)

如何使它如此具体的条目没有添加到列表中

2 个答案: