Python 索引超出范围异常

Question

I've tried this:

x = []
for i in range(5)
    x[i] = 0
print(x)

But it gives index out of range exception Why?

Answer 1

Because there is not any value in list that's why In this case you have to use append

like

x = []
for i in range(5)
    x.append(0) #x[i] = 0 
print(x)

remove this line x[i] = 0 and put x.append(0)

Answer 2

You're getting a index out of range exception because there is nothing in your list. If you want to loop 5 times and set x[i] = 0 there has to be a x[i] first.

Answer 3

You created an empty list x = [] (not an array) and in a line x[i] = 0 where you are trying to assign element 0 with index=0 which does not exist at the time of initialization, here in your case it will be the first iteration of for loop with i=0 .

Here is the example:

>>> x = []
>>> x[0] = 0
 Traceback (most recent call last):
 File "<pyshell#8>", line 1, in <module>
    x[0] = 0
 IndexError: list assignment index out of range

It will not allow you to assign element with index to an empty list.