如何在Python中追加列表而不重写？

Question

country = ["Denmark", "Croatia", "Britian", "Canada"]
for idx, val in enumerate(country):
    d = []
    d.append(idx)
    print(d)

我正在学习如何在列表中添加索引，但我一直在覆盖我的迭代。你能帮忙吗

Answer 1

country = ["Denmark", "Croatia", "Britian", "Canada"]
d = []
for idx, val in enumerate(country):
    d.append(idx)
    print(d)

您需要将d的定义放在循环之外，否则在每次迭代中，d再次变成一个空列表

Answer 2

d在每次进入循环时被实例化为null，请在循环外部定义它

country = ["Denmark", "Croatia", "Britian", "Canada"]
d = []
for idx, val in enumerate(country):
   
    d.append(idx)
print(d)

Answer 3

country = ["Denmark", "Croatia", "Britian", "Canada"]
d = []
for i,v in enumerate(country):
    d.append(v)


for i in range(0,4):
    print(country[i])

输出

丹麦

克罗地亚

英国人

加拿大