Python 如何更改日历列表中的值？

我的函数的目标是在该日历中预订一个与参数day和time相对应的时段-通过将日历中的值更改为“X”（表示已预订日期/时间）来完成预订。以下是我目前掌握的代码：

def find_index(val, seq):
    for index in range(len(seq)):
        place = seq[index]
        if place == val:
            return index
        else:
            return int("-1")

def init_nested_list(size_outer, size_inner):
    cal = []
    for outer_index in range(size_outer):
        nested_list = []
        for inner_index in range(size_inner):
            nested_list.append("-")
        cal.append(nested_list)
    return cal

def book_slot(cal,days_labels, times_labels, day, time):
    pos1 = find_index(day, days_labels)
    desired_day = cal[pos1]
    pos2 = find_index(time, times_labels)
    desired_time = desired_day[pos2]
    if desired_day == "X":
        print("We are sorry - that time is not available. Please try again.")
    else:
        print("Appointment is booked.")


days_labels = ["Wednesday","Thursday","Friday"]
times_labels = ["9","10","11"]
cal = init_nested_list(len(days_labels), len(times_labels))
print("before" , cal)
book_slot(cal, days_labels, times_labels, "Friday", "10")
print("after" , cal)

这是我得到的输出：

before [['-', '-', '-'], ['-', '-', '-'], ['-', '-', '-']]
Appointment is booked.
after [['-', '-', '-'], ['-', '-', '-'], ['-', '-', '-']]

这是我应该得到的输出：

before [['-', '-', '-'], ['-', '-', '-'], ['-', '-', '-']]
Appointment is booked.
after [['-', '-', '-'], ['-', '-', '-'], ['-', 'X', '-']]
We are sorry - that time is not available. Please try again.

---

如您所见，正确的输出将记录嵌套列表中的第二个元素（星期五，第10页），但对于我的代码来说，它不是。我知道desired_day是用户希望预订的cal中的一天，但我不确定如何正确获取它，并在用户预订时将其分配给字符串“X”。我也知道book_slot函数中有一个编码错误导致了这种情况，但我再一次不确定它是什么…请帮助？

在

book_slot中没有任何地方

您是否将

X

分配给任何东西。我认为您可以使用

pos1

和

pos2

来确定要分配到的插槽。

这将起作用。请参阅代码中的更改#注释

def find_index(val, seq):
    return seq.index(val) #Change 1


def init_nested_list(size_outer, size_inner):
    cal = []
    for outer_index in range(size_outer):
        nested_list = []
        for inner_index in range(size_inner):
            nested_list.append("-")
        cal.append(nested_list)
    return cal


def book_slot(cal, days_labels, times_labels, day, time):
    pos1 = find_index(day, days_labels)
    desired_day = cal[pos1]
    pos2 = find_index(time, times_labels)
    if desired_day[pos2] is "X": # Change 2
        print("We are sorry - that time is not available. Please try again.")
    else:
        print("Appointment is booked.")
        desired_day[pos2] = "X" # Change 3


days_labels = ["Wednesday", "Thursday", "Friday"]
times_labels = ["9", "10", "11"]
cal = init_nested_list(len(days_labels), len(times_labels))
print("before", cal)
book_slot(cal, days_labels, times_labels, "Friday", "10")
book_slot(cal, days_labels, times_labels, "Friday", "10") # Change 4: Need to do a booking twice to make it fail :-)
print("after", cal)

将输出：

('before', [['-', '-', '-'], ['-', '-', '-'], ['-', '-', '-']])
Appointment is booked.
('after', [['-', '-', '-'], ['-', '-', '-'], ['-', 'X', '-']])
We are sorry - that time is not available. Please try again.