如何查找并打印与用户输入匹配的字典 key/value？

Question

我需要打印一个与用户输入匹配的字典值。例如，如果用户输入课程编号 CS101，输出将如下所示：

The details for CS101 are:
Room: 3004
Instructor: Haynes
Time: 8:00 a.m.

但是，如果用户输入 incorrect/invalid 课程编号，我需要打印一条消息让他们知道：

CS101 is an invalid course number.

我已经尝试了 if、for loops 和 while loops。问题是，每次我打印课程信息时，由于 KeyError，无效课程编号消息不会显示。另一方面，如果我碰巧“修复”了错误消息，那么课程编号信息将不会打印出来，而是 return 一个 NameError / TypeError。老实说，我已经为此苦苦挣扎了一段时间，我觉得我要么分配不正确，要么打印不正确。但是我是初学者，我还没有很好地掌握 Python ，这就是我寻求帮助的原因。不幸的是，不允许我创建一个完整的字典来对所有内容进行分组（这对我来说会更容易），而是我必须创建 3 个字典。这是代码：

room = {}

room["CS101"] = "3004"
room["CS102"] = "4501"
room["CS103"] = "6755"
room["NT110"] = "1244"
room["CM241"] = "1411"

instructor = {}

instructor["CS101"] = "Haynes"
instructor["CS102"] = "Alvarado"
instructor["CS103"] = "Rich"
instructor["NT110"] = "Burkes"
instructor["CM241"] = "Lee"

time = {}

time["CS101"] = "8:00 a.m."
time["CS102"] = "9:00 a.m."
time["CS103"] = "10:00 a.m."
time["NT110"] = "11:00 a.m."
time["CM241"] = "1:00 p.m."

def info():
    print(f'College Course Locater Program')
    print(f'Enter a course number below to get information')

info()
get_course = input(f'Enter course number here: ')
print(f'----------------------------------------------')

course_num = get_course
number = course_num
name = course_num
meeting = course_num

if number in room:
    if name in instructor:
        if meeting in time:
            print(f'The details for course {get_course} are: ')
            print(f'Room: {number["room"]}')
            print(f'Instructor: {name["instructor"]}')
            print(f'Time: {meeting["time"]}')
else:
    print(f'{course_num} is an invalid course number.')

我也试过用这种风格格式化字典：

time_dict = {
    "CS101": {
        "Time": "8:00 a.m."
    },
    "CS102": {
        "Time": "9:00 a.m."
    },
    "CS103": {
        "Time": "10:00 a.m."
    },
    "NT110": {
        "Time": "11:00 a.m."
    },
    "CM241": {
        "Time": "1:00 p.m."
    },
}

我提前感谢所有对解决方案有建议、回答或建议的人。

Answer 1

此处的代码是不必要的，因为您实质上是将 4 个变量都设置为相同的值 get_course:

course_num = get_course
number = course_num
name = course_num
meeting = course_num

此处的代码不起作用，因为您试图在不存在的字典中查找带有字符串“room”的键，之后的其他行也是如此

print(f'Room: {number["room"]}')
print(f'Instructor: {name["instructor"]}')
print(f'Time: {meeting["time"]}')

我将上面的代码替换为：

print(f'Room: {room[get_course]}')
print(f'Instructor: {instructor[get_course]}')
print(f'Time: {time[get_course]}')

这会在字典变量 room 中搜索键 get_course（例如“CS101”）和 returns 对应于该键的值。除了字典讲师和字典时间之外，其他行也会发生同样的事情。

这是最终代码：

room = {}

room["CS101"] = "3004"
room["CS102"] = "4501"
room["CS103"] = "6755"
room["NT110"] = "1244"
room["CM241"] = "1411"

instructor = {}

instructor["CS101"] = "Haynes"
instructor["CS102"] = "Alvarado"
instructor["CS103"] = "Rich"
instructor["NT110"] = "Burkes"
instructor["CM241"] = "Lee"

time = {}

time["CS101"] = "8:00 a.m."
time["CS102"] = "9:00 a.m."
time["CS103"] = "10:00 a.m."
time["NT110"] = "11:00 a.m."
time["CM241"] = "1:00 p.m."

def info():
    print(f'College Course Locater Program')
    print(f'Enter a course number below to get information')

info()
get_course = input(f'Enter course number here: ')
print(f'----------------------------------------------')


if get_course in room and get_course in instructor and get_course in time:
    print(f'The details for course {get_course} are: ')
    print(f'Room: {room[get_course]}')
    print(f'Instructor: {instructor[get_course]}')
    print(f'Time: {time[get_course]}')
else:
    print(f'{get_course} is an invalid course number.')

这是输入“CS101”的测试：

College Course Locater Program
Enter a course number below to get information
Enter course number here: CS101
----------------------------------------------
The details for course CS101 are:
Room: 3004
Instructor: Haynes
Time: 8:00 a.m.

Answer 2

你也可以这样做。它可能需要更少的时间。该功能不是很有条理，试着稍微组织一下，它应该可以工作。我对在这里添加代码还不是很熟悉。

course_info = {
'CS101': {
    'Room': '3004',
    'Instructor': 'Haynes',
    'Time': '8:00 am'
},
'CS102': {
    'Room': '4501',
   'Instructor': 'Alvarado',
   'Time': '9:00 a.m.'
},
'CS103': {
    'Room': '6755',
    'instructor': 'Rich',
    'Time:': '10:00 am',
},
'NT110': {
    'Room': '1244',
    'instructor': 'Burkes',
    'Time': '11:00 am'
},
'CM241': {
    'Room': '1411',
    'Instructor': 'Lee',
    'Time': '1:00 pm'
},

}

get_course = input(f'Enter a course number: ')

try:
   courses = course_info[get_course]
   print(f'The details for for course {get_course} are: ')
   print(f"Room: {courses['Room']}, Time: {courses['Time']}, 
                   Instructor: {courses['Instructor']}")
except KeyError:
   print(f'Details not found for {get_course}')

如何查找并打印与用户输入匹配的字典 key/value？

How to find and print a dictionary key/value that matches user input?

dictionary

input

key-value

python-3.8