Python列表插入（）

Python List insert()方法是Python中的一个内置函数，可在列表中的给定索引处插入给定元素。

Syntax:

list_name.insert(index, element)

Parameters: 

• index: the index at which the element has to be inserted.
• element: the element to be inserted in the list.

Returns: 

This method does not return any value but it inserts the given element at the given index.

Error:

If anything other than a list is used with insert(), then it returns an AttributeError.

Note: 

If given index >= length(list) is given, then it inserts at the end of the list.

示例 1：将元素插入列表

Python3

# Python3 program for use  
# of insert() method 
  
list1 = [ 1, 2, 3, 4, 5, 6, 7 ] 
  
# insert 10 at 4th index 
list1.insert(4, 10) 
print(list1) 
  
list2 = ['a', 'b', 'c', 'd', 'e'] 
  
# insert z at the front of the list
list2.insert(0, 'z')
print(list2)

输出：

[1, 2, 3, 4, 10, 5, 6, 7]
['z', 'a', 'b', 'c', 'd', 'e']

示例 2： insert() 方法的错误

Python3

# Python3 program for error  
# of insert() method 
  
# attribute error 
string = "1234567"
  
string.insert(10, 1)
print(string)

输出：

Traceback (most recent call last):
  File "/home/2fe54bd8723cd0ae89a17325da8b2eb5.py", line 7, in 
    string.insert(10, 1)
AttributeError: 'str' object has no attribute 'insert'

示例 3：在列表中的任何元素之前插入

Python3

# Python3 program for Insertion in a list  
# before any element using insert() method 
  
list1 = [ 1, 2, 3, 4, 5, 6 ]
  
# Element to be inserted 
element = 13 
  
# Element to be inserted before 3
beforeElement = 3 
  
# Find index
index = list1.index(beforeElement) 
  
# Insert element at beforeElement 
list1.insert(index, element) 
print(list1)

输出：

[1, 2, 13, 3, 4, 5, 6]

示例 4：将元组插入列表

Python3

list1 = [ 1, 2, 3, 4, 5, 6 ]
  
# tuple of numbers
num_tuple = (4, 5, 6)
  
# inserting a tuple to the list
list1.insert(2, num_tuple)
  
print(list1)

输出：

[1, 2, (4, 5, 6), 3, 4, 5, 6]