“你想继续吗？”的问题Python中的类型案例

Question

这是场景：

我有一个要求用户输入的功能 - 从 n 个项目的列表中选择 m 个项目（给定 m n)。仅供参考，如果他愿意，他可能会输入错误的值，在这种情况下，他会被问到是否要重新开始，但如果他输入了正确的值，那就没问题了。我被前一部分卡住了。

这是我的代码，我知道它是错误的，所以不需要惩罚我！

column_names = ["DWUXZ", "bKDoH", "erLlI", "QJAfR", "dAfNn", "kpwGt", "fuDmY", "WoTau", "qrFaZ", "ZGSkx"] #The list to choose the items from

def newfunc():

    print (f"Here is the list of columns to choose from: {column_names}\n"
    args = input ("Enter column names separated by comma (Hit enter to select all columns).\n").split(',')

    userinputs_notfound = [] #This will hold the wrong entries entered by the user.
    for arg in args:
        if arg.replace(" ", "") not in column_names:
            userinputs_notfound.append(arg.replace(" ", ""))
    
    if len(userinputs_notfound) == 0:
        pass
    else:
        while input("Do you want to continue? [Y/n]: ").lower() == 'y':
            newfunc() #Recursively calling the function

newfunc() #Calling the function.

我无法正确处理 while 部分。简而言之，这就是我想做的事情：

1. 用户可以选择从给定列表中选择字符串（称为column_names）
2. 他故意输入错误的值
3. 脚本显示“未找到这些条目。您要再试一次吗？[Y/n]”
4. 当用户点击 Y 时，它会返回并再次执行整个操作。
5. 如果他选择否，则退出循环

为了我的一生，我无法做到这一点。

非常感谢任何帮助。

Answer 1

这个是python 3.8+的

# The list to choose from
col_names = ["DWUXZ", "bKDoH", "erLlI", "QJAfR", "dAfNn", "kpwGt", "fuDmY", "WoTau", "qrFaZ", "ZGSkx"]

def newFunc():
    # Print all the available column names.
    print("List of columns to choose from:\n", *col_names, sep = '\n')

    # Filter out the missing names (if any) and ask for the prompt.
    # The anonymous function inside lambda match against the empty
    # string when the user chooses to select all.
    while missing := list(filter(lambda name: name and name not in col_names,
    input("\nEnter column names separated by comma (Hit enter to select all): ").split(','))):
        
        print("Missing:", *missing, sep = '\n')
        # Break the loop for any of the negetive response.
        if input("\nDo you want to continue? ").lower() in ['n', "no", "nope", "nah"]:
            break

    # Implement here your logic when no missing is found.


# Call the function.
newFunc()

在赋值运算符:= 的帮助下，我们在几行代码内完成了这项工作。

Answer 2

要么将整个函数体放在 for 循环中，而将递归调用省略为：

def foo():
    while x:
        do_stuff
        change_x

或省略while循环并使用条件if语句保持递归：

def foo():
    do_stuff
    if condition:
        foo()

否则您会继续调用该函数，因此您需要转义您在程序运行期间创建的每个 while input() == 'y' 循环，无论可能有多少。

至于'按回车键保持选择所有列：

if arg == ['']:
    arg = column_names

检查['']，因为您拆分了用户输入。

Answer 3

column_names = ["DWUXZ", "bKDoH", "erLlI", "QJAfR", "dAfNn", "kpwGt", "fuDmY", "WoTau", "qrFaZ", "ZGSkx"]

def newfunc():

print (f"Here is the list of columns to choose from: {column_names}\n") //correction
args = input("Enter column names separated by comma (Hit enter to select all columns).\n").split(',')

userinputs_notfound = [] #This will hold the wrong entries entered by the user.
for arg in args:
    if arg.replace(" ", "") not in column_names:
        userinputs_notfound.append(arg.replace(" ", ""))

if len(userinputs_notfound) == 0:
    pass
else:
    if input("Do you want to continue? [Y/n]: ").lower() == 'y': //correction no need of while
        newfunc()

newfunc() #Calling the function.

Answer 4

对您的代码进行了一些重构：

（也解决了“输入以选择所有列”的问题。）

# The list to choose the items from
column_names = ["DWUXZ", "bKDoH", "erLlI", "QJAfR", "dAfNn", "kpwGt",
                "fuDmY", "WoTau", "qrFaZ", "ZGSkx"]

def get_input():
    print(f"Here is the list of columns to choose from: {column_names}\n")
    args = input("Enter column names separated by comma "
                  "(Hit enter to select all columns).\n").strip().split(',')
    return args


while True:
    args = get_input()
    if len(args) == 1 and args[0] == '':  # pressed enter
        print('OK. Selected all columns')
        break

    # This will hold the wrong entries entered by the user.
    userinputs_notfound = []
    for arg in args:
        if arg.replace(" ", "") not in column_names:
            userinputs_notfound.append(arg.replace(" ", ""))

    if not userinputs_notfound:
        print('OK')
        break

    should_quit = input("Do you want to continue? [Y/n]: ").lower() == 'n'
    if should_quit is True:
        break

输出：

Here is the list of columns to choose from: ['DWUXZ', 'bKDoH', 'erLlI', 'QJAfR', 'dAfNn', 'kpwGt', 'fuDmY', 'WoTau', 'qrFaZ', 'ZGSkx']

Enter column names separated by comma (Hit enter to select all columns).
DWUXZ, bKDoH
OK

Here is the list of columns to choose from: ['DWUXZ', 'bKDoH', 'erLlI', 'QJAfR', 'dAfNn', 'kpwGt', 'fuDmY', 'WoTau', 'qrFaZ', 'ZGSkx']

Enter column names separated by comma (Hit enter to select all columns).
fda, fdax
Do you want to continue? [Y/n]: n

Here is the list of columns to choose from: ['DWUXZ', 'bKDoH', 'erLlI', 'QJAfR', 'dAfNn', 'kpwGt', 'fuDmY', 'WoTau', 'qrFaZ', 'ZGSkx']

Enter column names separated by comma (Hit enter to select all columns).
fda, dax
Do you want to continue? [Y/n]: y
Here is the list of columns to choose from: ['DWUXZ', 'bKDoH', 'erLlI', 'QJAfR', 'dAfNn', 'kpwGt', 'fuDmY', 'WoTau', 'qrFaZ', 'ZGSkx']

Enter column names separated by comma (Hit enter to select all columns).

Here is the list of columns to choose from: ['DWUXZ', 'bKDoH', 'erLlI', 'QJAfR', 'dAfNn', 'kpwGt', 'fuDmY', 'WoTau', 'qrFaZ', 'ZGSkx']

Enter column names separated by comma (Hit enter to select all columns).

OK. Selected all columns

Answer 5

整个主体应该处于一个 while 循环中，一旦输入正确，您就会中断该循环。不要像这样以无限的方式使用递归。

column_names = set(["DWUXZ", "bKDoH", "erLlI", "QJAfR", "dAfNn", "kpwGt", "fuDmY", "WoTau", "qrFaZ", "ZGSkx")

def newfunc():

    while True:
        print (f"Here is the list of columns to choose from: {column_names}\n"
        args = input ("Enter column names separated by comma (Hit enter to select all columns).\n").split(',')
        if all(arg.replace(" ", "") in column_names for arg in args):
            break
           
        missing = set(args) - column_names
        if missing:
            print(f"Missing: {missing}")
            response = input("Do you want to try again?")
            if response.lower() == "n":
                break