Given a list and we have to add an element at specified index in Python.

给定一个列表，我们必须在Python中的指定索引处添加一个元素。

list.appened() Method is used to append/add an element at the end of the list. But, if we want to add an element at specified index, we use insert() method. It takes 2 arguments, index and element.

list.appened()方法用于在列表末尾添加/添加元素。 但是，如果要在指定的索引处添加元素，则可以使用insert()方法。 它需要2个参数， index和element 。

Syntax:

句法：

 list.insert(index, element)

Here,

这里，

• list is the name of the list, in which we have to insert element at given index.

  list是列表的名称，我们必须在其中给定index插入元素 。

• index is the position, where we want to insert an element.

  index是我们要插入元素的位置。

• element is an element/item to be inserted in the list.

  element是要在列表中插入的元素/项目。

Example:

例：

    list.insert(2, 100)
It will insert 100 at 2nd position in the list name ‘list’.

Program:

程序：

# Declaring a list
list = [10, 20, 30]
# printing elements
print (list)
# O/P will be: [10, 20, 30]
# inserting "ABC" at 1st index
list.insert (1, "ABC")
# printing
print (list)
# O/P will be: [10, 'ABC', 20, 30]
# inserting "PQR" at 3rd index
list.insert (3, "PQR")
# printing
print (list)
# O/P will be: [10, 'ABC', 20, 'PQR', 30]
# inserting 'XYZ' at 5th index
list.insert (5, "XYZ")
print (list)
# O/P will be: [10, 'ABC', 20, 'PQR', 30, 'XYZ']
# inserting 99 at second last index 
list.insert (len (list) -1, 99)
# printing
print (list)
# O/P will be: [10, 'ABC', 20, 'PQR', 30, 99, 'XYZ']

Output

输出量

    [10, 20, 30]
[10, 'ABC', 20, 30]
[10, 'ABC', 20, 'PQR', 30]
[10, 'ABC', 20, 'PQR', 30, 'XYZ']
[10, 'ABC', 20, 'PQR', 30, 99, 'XYZ']

翻译自: https://www.includehelp.com/python/add-an-element-at-specified-index-in-a-list.aspx