Python之列表基础

编程
0 字 / 约 0 分钟
2020/1/30
  1. 定义列表 python中用中括号[]表示列表，列表元素用逗号（,）隔开
python
>>> cells = ['cellA','cellB','cellC'] >>> print(cells) ['cellA', 'cellB', 'cellC']

定义一个空的列表

python
>>> cells = [] >>> print(cells) []
  1. 索引介绍及访问列表元素 python列表中，索引是从0开始的，而不是1，所以第一个元素索引为0。
python
>>> cells = ['cellA','cellB','cellC'] 
>>> print(cells[0]) cellA 
>>> print(cells[1]) cellB 
>>> print(cells[2]) cellC 
>>> print(cells[-1]) 
#指定索引[-1]可以让python返回列表最后一个元素。 
cellC 
>>> print(cells[-2]) 
#指定索引[-2]可以让python返回列表倒数第二个元素。 
cellB
  1. 修改列表元素
python
>>> cells = ['cellA','cellB','cellC'] 
>>> print(cells) ['cellA', 'cellB', 'cellC'] 
>>> cells[0] = 'blockA' 
>>> print(cells) ['blockA', 'cellB', 'cellC']
  1. 添加元素到列表"append"
python
>>> cells = ['cellA','cellB','cellC'] 
>>> cells.append('cellD') 
>>> print(cells) ['cellA', 'cellB', 'cellC', 'cellD']
  1. 列表中插入元素"insert"
python
>>> cells = ['cellA','cellB','cellC'] 
>>> cells.insert(0,'cellX') 
>>> print(cells) ['cellX', 'cellA', 'cellB', 'cellC']
  1. 删除列表中的元素"del"
python
>>> cells = ['cellA','cellB','cellC'] 
>>> del cells[0] >>> print(cells) ['cellB', 'cellC'] 
>>> cells = ['cellA','cellB','cellC'] 
>>> del cells[-1] >>> print(cells) ['cellA', 'cellB']
  1. 弹出列表中指定元素“pop()”
python
>>> cells = ['cellA','cellB','cellC'] 
>>> second_cell = cells.pop(1) 
>>> print('The second cell is '+ second_cell + '.') 
The second cell is cellB. 
>>> print(cells) ['cellA', 'cellC'] 
#索引[1]被弹出后已自动从列表中删除
  1. 根据索引值删除列表中元素“remove()”
python
>>> cells = ['cellA','cellB','cellC','cellA'] 
>>> cells.remove('cellA') 
>>> print(cells) ['cellB', 'cellC', 'cellA'] 
#revome只会删除第一个指定的值
  1. 永久性排序列表“sort()”
python
>>> cells = ['cellB','cellD','cellC','cellA'] 
>>> cells.sort() 
>>> print(cells) ['cellA', 'cellB', 'cellC', 'cellD']

sort（reverse=True)可以反向排序

python
>>> cells = ['cellB','cellD','cellC','cellC'] 
>>> cells.sort(reverse=True) 
>>> print(cells) ['cellD', 'cellC', 'cellC', 'cellB']
  1. 临时性排序列表"sorted()" sorted不会永久改变列表顺序，只是临时的
python
>>> cells = ['cellB','cellD','cellC','cellA'] 
>>> print('original list is:');print(cells) original list is: ['cellB', 'cellD', 'cellC', 'cellA'] 
>>> print('sorted list is:');print(sorted(cells)) sorted list is: ['cellA', 'cellB', 'cellC', 'cellD'] 
>>> print('original list is:');print(cells) original list is: ['cellB', 'cellD', 'cellC', 'cellA']
  1. 反转列表"reverse"
python
>>> cells =['cellA', 'cellB', 'cellC', 'cellD'] 
>>> print(cells) ['cellA', 'cellB', 'cellC', 'cellD'] 
>>> cells.reverse() 
>>> print(cells) ['cellD', 'cellC', 'cellB', 'cellA']
  1. 获取列表长度"len"
python
>>> cells =['cellA', 'cellB', 'cellC', 'cellD'] 
>>> len(cells) 4