如何在Python中将元素添加到列表

In this tutorial, we will learn different ways to add elements to a List in Python.

在本教程中，我们将学习使用Python向列表中添加元素的不同方法。

在Python中向List添加元素的方法 (Methods to add elements to List in Python)

There are four methods to add elements to a List in Python.

有四种方法可以在Python中将元素添加到列表中。

append(): append the object to the end of the list.append（）：将对象追加到列表的末尾。
insert(): inserts the object before the given index.insert（）：在给定索引之前插入对象。
extend(): extends the list by appending elements from the iterable.extend（）：通过添加来自iterable的元素来扩展列表。
List Concatenation: We can use + operator to concatenate multiple lists and create a new list.列表串联：我们可以使用+运算符来串联多个列表并创建一个新列表。

Python将元素添加到列表示例 (Python add elements to List Examples)

We can add an element to the end of the list or at any given index. There are ways to add elements from an iterable to the list. We can also use + operator to concatenate multiple lists to create a new list.

我们可以将元素添加到列表的末尾或任何给定的索引处。有一些方法可以将元素从可迭代对象添加到列表中。我们还可以使用+运算符连接多个列表以创建新列表。

1. append（） (1. append())

This function add the element to the end of the list.

此函数将元素添加到列表的末尾。

fruits = ["Apple", "Banana"]# 1. append()
print(f'Current Fruits List {fruits}')f = input("Please enter a fruit name:\n")
fruits.append(f)print(f'Updated Fruits List {fruits}')

Output:

输出：

Current Fruits List ['Apple', 'Banana']
Please enter a fruit name:
Orange
Updated Fruits List ['Apple', 'Banana', 'Orange']

2. insert（） (2. insert())

This function adds an element at the given index of the list. It’s useful to add an element at the specified index of the list.

此函数在列表的给定索引处添加一个元素。在列表的指定索引处添加元素很有用。

num_list = [1, 2, 3, 4, 5]print(f'Current Numbers List {num_list}')num = int(input("Please enter a number to add to list:\n"))index = int(input(f'Please enter the index between 0 and {len(num_list) - 1} to add the number:\n'))num_list.insert(index, num)print(f'Updated Numbers List {num_list}')

Output:

输出：

Current Numbers List [1, 2, 3, 4, 5]
Please enter a number to add to list:
20
Please enter the index between 0 and 4 to add the number:
2
Updated Numbers List [1, 2, 20, 3, 4, 5]

3.extend（） (3. extend())

This function append iterable elements to the list. It is useful to append elements from an iterable to the end of the list.

此函数将可迭代元素添加到列表中。将元素从可迭代对象追加到列表的末尾很有用。

list_num = []
list_num.extend([1, 2])  # extending list elements
print(list_num)
list_num.extend((3, 4))  # extending tuple elements
print(list_num)
list_num.extend("ABC")  # extending string elements
print(list_num)

Output:

输出：

[1, 2]
[1, 2, 3, 4]
[1, 2, 3, 4, 'A', 'B', 'C']

4.列表串联 (4. List Concatenation)

If you have to concatenate multiple lists, you can use the “+” operator. This will create a new list and the original lists will remain unchanged.

如果必须串联多个列表，则可以使用“ +”运算符。这将创建一个新列表，而原始列表将保持不变。

evens = [2, 4, 6]
odds = [1, 3, 5]nums = odds + evens
print(nums)  # [1, 3, 5, 2, 4, 6]

The new list will contain elements from the list from left to right. It’s similar to the string concatenation in Python.

新列表将包含列表中从左到右的元素。它类似于Python中的字符串连接。

结论 (Conclusion)

It’s very easy to add elements to a List in Python programming. We can append an element at the end of the list, insert an element at the given index. We can also add a list to another list. If you want to concatenate multiple lists, then use the overloaded + operator.

在Python编程中将元素添加到列表非常容易。我们可以在列表的末尾追加一个元素，在给定的索引处插入一个元素。我们还可以将一个列表添加到另一个列表。如果要串联多个列表，请使用重载的+运算符。

References:

参考文献：

Python ListPython清单
Python.org DocsPython.org文件

翻译自: https://www.journaldev.com/33182/python-add-to-list