Fibonacci与Python:indexer:list索引超出范围

我试图编写一个程序，用Python计算斐波那契数：

n = int(input())

def fib(n):
    a = []
    if (n <=1):
        return n
    else:
        for i in range(2, n):
            a.append(a[-1] + a[-2])
        return a[i]
print (fib(n))

但是，我无法打印出预期的结果。例如，我输入数字8后，弹出以下消息：

Traceback (most recent call last):
  File "fibonacci.py", line 11, in <module>
    print (fib(n))
  File "fibonacci.py", line 9, in fib
    a.append(a[-1] + a[-2])
IndexError: list index out of range

---

过程中出了什么问题？提前感谢。

您需要用Fibonacci序列的前两个数字填充列表：

a = [0, 1]

---

您需要使用Fibonacci序列的前两个数字填充列表：

a = [0, 1]

---

-如果在使用之前未在列表中设置2和-1索引，则它们不可用

n = int(input())

def fib(n):
    a = [0, 1]
    if n <=1:
        return n
    else:
        for i in range(2, n):
            a.append(a[-1] + a[-2])
        return a[i]
print (fib(n))

---

-如果在使用之前未在列表中设置2和-1索引，则它们不可用

n = int(input())

def fib(n):
    a = [0, 1]
    if n <=1:
        return n
    else:
        for i in range(2, n):
            a.append(a[-1] + a[-2])
        return a[i]
print (fib(n))

---

在代码中进行这些更改

n = int(input())

def fib(n):
    a = [0,1]  # add these values to your array to intialize
    if (n <=1):
        return n
    else:
        for i in range(2, n):
            a.append(a[-1] + a[-2])
    return a  # change this also so that you can get all the values returned at the same time

print (fib(n))

---

在代码中进行这些更改

n = int(input())

def fib(n):
    a = [0,1]  # add these values to your array to intialize
    if (n <=1):
        return n
    else:
        for i in range(2, n):
            a.append(a[-1] + a[-2])
    return a  # change this also so that you can get all the values returned at the same time

print (fib(n))

---

调用此函数来计算任何斐波那契数列

def Fibonacci(n): 
    if n<0: 
        print("Incorrect input") 
# First Fibonacci number is 0 
    elif n==0: 
        return 0
# Second Fibonacci number is 1 
    elif n==1: 
        return 1
    else: 
        return Fibonacci(n-1)+Fibonacci(n-2)

---

调用此函数来计算任何斐波那契数列

def Fibonacci(n): 
    if n<0: 
        print("Incorrect input") 
# First Fibonacci number is 0 
    elif n==0: 
        return 0
# Second Fibonacci number is 1 
    elif n==1: 
        return 1
    else: 
        return Fibonacci(n-1)+Fibonacci(n-2)

索引器错误：列出索引超出范围您的e从空数组开始并尝试访问其上的索引。索引器错误：列出索引超出范围您的e从空数组开始并尝试访问其上的索引。