Question

完全不熟悉Python，所以请耐心等待。

我通过raw_input创建了一个列表：

itemList = []
num = int (raw_input("Enter a number: "))
for i in range (num):
    listStr = raw_input("Enter an item: ")
    itemList.append (listStr)

现在我必须检查是否有任何项目，以及是否确实要求另一个raw_input添加到列表中。我完全难过了。这不是循环的;它只是打印一个。我还必须将新项目附加到原始列表。难住了。

itemList = []
num = int (raw_input("Enter a number: "))
for i in range (num):
    listStr = raw_input("Enter an item: ")
    itemList.append (listStr)
for a in itemList:
    if a in itemList :
        a = raw_input("Enter another number: ")

Answer 1

您可以使用while循环继续询问输入，直到输入的项目已经不在列表中。这可以改进，但它应该让你开始：

itemList = []
num = int (raw_input("Enter a number: "))

for i in range (num):

    while True:
        listStr = raw_input("Enter an item: ")
        if listStr in itemList:
            print('That item is already in the list')
        else:
            itemList.append(listStr)
            break

稍微好一点的版本：

itemList = []
num = int(raw_input("Enter a number: "))

for i in range(num):

    listStr = raw_input("Enter an item: ")

    while listStr in itemList:
        print("That item already exists")
        listStr = raw_input("Enter another number: ")

    itemList.append(listStr)

Answer 2

以下是代码的略微修改版本

itemList = []
num = int (raw_input("Enter a number: "))
for i in range (num):
    listStr = raw_input("Enter an item: ")
    itemList.append (listStr)
for idx in range(len(itemList)):
    # using a while ensures that if the value newly entered
    # is again present in the list, it again prompts for an input
    while itemList[idx] in itemList[:idx] or itemList[idx] in itemList[idx+1:] :
        a = raw_input("Enter a replacement for item {0}: ".format(itemList[idx]))
        itemList[idx] = a

通过raw_input替换列表中的重复项

2 个答案: