我正在嘗試創(chuàng)建一個購物清單。目標(biāo)是逐個輸入每個雜貨店，然后列出“購物已完成?！?，但是當(dāng)我編寫代碼時，我只能從列表中輸入第一個雜貨店，然后雜貨店列表的其余部分會自動將其列到最后。我的代碼有什么問題？listanamirnica = ["Bananas 1kg", "Bread 5x", "Milk 1l", "Apples 3kg"]print("Things i need to buy: ",listanamirnica)num_shoping = 0num_items = len(listanamirnica)print("Total number of items need to buy: ", num_items)i_buyed = input("I buyed: ")while num_shoping != num_items: if i_buyed.lower() == "bananas": del listanamirnica[0] print("Left to buy: ", listanamirnica) num_shoping += 1 continue elif i_buyed.lower() == "bread": del listanamirnica[1] i_buyed = input("I buyed: ") print("Left to buy: ", listanamirnica) num_shoping += 1 continue elif i_buyed.lower() == "milk": del listanamirnica[2] i_buyed = input("I buyed: ") print("Left to buy: ", listanamirnica) num_shoping += 1 continue elif i_buyed.lower() == "apples": del listanamirnica[3] i_buyed = input("I buyed: ") print("Left to buy: ", listanamirnica) num_shoping += 1 continueprint("You buyed all groceries.")我希望在輸入“bananas”后再次輸入“我買了：”，然后輸入 mlik apples bread。
3 回答
神不在的星期二
TA貢獻(xiàn)1963條經(jīng)驗(yàn) 獲得超6個贊
您的代碼中存在一些問題，已在下面更正
listanamirnica = ["Bananas 1kg", "Bread 5x", "Milk 1l", "Apples 3kg"]
print("Things i need to buy: ",listanamirnica)
num_shoping = 0
num_items = len(listanamirnica)
print("Total number of items need to buy: ", num_items)
while num_shoping != num_items:
i_buyed = input("I buyed: ")
if i_buyed.lower() == "bananas":
listanamirnica.remove("Bananas 1kg")
print("Left to buy: ", listanamirnica)
num_shoping += 1
elif i_buyed.lower() == "bread":
listanamirnica.remove("Bread 5x")
print("Left to buy: ", listanamirnica)
num_shoping += 1
elif i_buyed.lower() == "milk":
listanamirnica.remove("Milk 1l")
print("Left to buy: ", listanamirnica)
num_shoping += 1
elif i_buyed.lower() == "apples":
listanamirnica.remove("Apples 3kg")
print("Left to buy: ", listanamirnica)
num_shoping += 1
print("You buyed all groceries.")
我所做的更改：
將輸入移到內(nèi)部，
while以便每次迭代都要求用戶輸入沒有必要
inputs從您的if案例中刪除。刪除
continue聲明，因?yàn)樗鼪]有必要，刪除
listanamirnica[0]并添加listanamirnica.remove("Bananas 1kg")為索引將在您刪除項(xiàng)目后更改，如果您不按指定順序刪除，那么0您硬編碼的索引將刪除錯誤的項(xiàng)目。
一只甜甜圈
TA貢獻(xiàn)1836條經(jīng)驗(yàn) 獲得超5個贊
你只需要把循環(huán)放在i_buyed = input("I buyed: ")里面while。
并從 each 中刪除它if/elif，它更加清晰和有條理。再加上你想一遍又一遍地寫同一行。另外，既然你elif在 while 循環(huán)中，你就不再需要continue了，因?yàn)樗粫M(jìn)入 otherif/elif而只是完成迭代。
listanamirnica = ["Bananas 1kg", "Bread 5x", "Milk 1l", "Apples 3kg"]
print("Things i need to buy: ",listanamirnica)
num_shoping = 0
num_items = len(listanamirnica)
print("Total number of items need to buy: ", num_items)
while num_shoping != num_items:
i_buyed = input("I buyed: ")
if i_buyed.lower() == "bananas":
del listanamirnica[0]
print("Left to buy: ", listanamirnica)
num_shoping += 1
elif i_buyed.lower() == "bread":
del listanamirnica[1]
print("Left to buy: ", listanamirnica)
num_shoping += 1
elif i_buyed.lower() == "milk":
del listanamirnica[2]
print("Left to buy: ", listanamirnica)
num_shoping += 1
elif i_buyed.lower() == "apples":
del listanamirnica[3]
print("Left to buy: ", listanamirnica)
num_shoping += 1
print("You buyed all groceries.")
Smart貓小萌
TA貢獻(xiàn)1911條經(jīng)驗(yàn) 獲得超7個贊
有兩個問題，首先，正如您自己注意到的input()那樣，第一個條件塊中缺少語句。第二個問題來自您刪除列表中項(xiàng)目的方式。使用的del風(fēng)險(xiǎn)很大，你應(yīng)該避免它。特別是，如果您從 enterin 開始bread，一切都很好，但是在刪除項(xiàng)目時，列表的索引會發(fā)生變化。所以apples會處于位置2。為了避免這種情況，您可以采取兩種方法： 1. 將列表替換為無序的集合，但您可以按名稱引用元素：
listanamirnica = {"Bananas 1kg", "Bread 5x", "Milk 1l", "Apples 3kg"}
...
listanamirnica.remove("Bread 5x")
只需將remove語句放在相應(yīng)調(diào)整的每個條件塊中即可。
如果您需要保持列表以下列方式更新它（同樣是面包部分）：
listanamirnica = [i for i in listanamirnica if i != "Bread 5x"]
第一種方法絕對是可取的，因?yàn)樵诘诙N方法中，您每次都創(chuàng)建一個新列表
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