python insert

list.insert()方法 (list.insert() Method)

insert() is an inbuilt method in python, which is used to add an element /item at specified index to the list.

insert()是python中的内置方法，用于将指定索引处的元素/ item添加到列表中。

insert() is able to add the element where we want i.e. position in the list, which we was not able to do the same in list.append() Method.

insert()能够将元素添加到我们想要的位置，即列表中的位置，而list.append()方法无法做到这一点 。

Syntax:

句法：

    list.insert(index, element)

Here,

这里，

• list is the name of the list.

  list是列表的名称。

• index is the valid value of the position/index.

  index是头寸/索引的有效值。

• element is an item/element to be inserted.

  元素是要插入的项目/元素。

Return type: Method insert() does not return any value, it just modifies the existing list.

返回类型：方法insert()不返回任何值，它仅修改现有列表。

Program:

程序：

# Python program to demonstrate
# an example of list.insert() method
# list
cities = ['New Delhi', 'Mumbai']
# print the list
print "cities are: ",cities
# insert 'Bangalore' at 0th index
index = 0
cities.insert(index,'Bangalore')
# insert 'Chennai' at 2nd index
index = 2
cities.insert(index, 'Chennai')
# print the updated list
print "cities are: ",cities

Output

输出量

    cities are:  ['New Delhi', 'Mumbai']cities are:  ['Bangalore', 'New Delhi', 'Chennai', 'Mumbai']

Explanation:

说明：

• Initially there were two elements in the list ['New Delhi', 'Mumbai'].

  最初，列表中有两个元素['New Delhi'，'Mumbai'] 。

• Then, we added two more city names (two more elements) - 1) 'Bangalore' at 0^th index and 2) 'Chennai' at 2^nd index after adding 'Bangalore' at 0^th index, by using following python statements:

  ：在0在^第二索引处0添加“班加罗尔” ^个索引，通过使用以下Python语句后1)“班加罗尔” ^个索引和2)“奈” -然后，我们增加了两个城市名称(两个元件)

# insert 'Bangalore' at 0th index
index = 0
cities.insert(index, 'Bangalore')
# insert 'Chennai' at 2nd index
index = 2
cities.insert(index, 'Chennai')

• After inserting 'Bangalore' at 0^th index, the list will be ['Bangalore', 'New Delhi', 'Chennai'].

  在^第 0 ^个索引处插入“班加罗尔”后，列表将为['Bangalore'，'New Delhi'，'Chennai'] 。

• And, then we added 'Chennai' at 2^nd index. After inserting 'Chennai' at 2^nd index. The list will be ['Bangalore', New Delhi', 'Chennai', 'Mumbai'].

  然后，我们在^第二个索引处添加了“ Chennai” 。 在^第二个索引处插入“ Chennai”之后。 该列表将是['Bangalore'，New Delhi'，'Chennai'，'Mumbai'] 。

• So, it is at our hand, what we have to do? If our requirement is to add an element at the end of the list - use list.append() Method, or if our requirement is to add an element at any index (any specified position) - use list.insert() Method.

  那么，这在我们眼前，我们该怎么办？ 如果我们的要求是在列表的末尾添加一个元素-使用list.append()方法 ，或者我们的要求是在任何索引(任何指定位置)添加一个元素-使用list.insert()方法。

  翻译自: https://www.includehelp.com/python/list-insert-method-with-example.aspx

  python insert