python学习-16 列表list

Posted 2022-02-18 liujinjing521

list

1.由[ ]括住，中括号内各元素由逗号隔开，各元素可以是数字，字符串，列表，布尔值等等。

例如：

li = [521,"love",["john","boy",12],True]
print(li)

ps:列表是可以嵌套的

2.取值

-索引取值：

li = [123,"love",[‘a‘,132,‘abc‘],"我爱你",True]
print(li[3])

输出结果：

我爱你

Process finished with exit code 0

-切片取值：

li = [123,"love",[‘a‘,132,‘abc‘],"我爱你",True]
print(li[1:5])

输出结果：

[‘love‘, [‘a‘, 132, ‘abc‘], ‘我爱你‘, True]

Process finished with exit code 0

-循环

li = [123,"love",[‘a‘,132,‘abc‘],"我爱你",True]
for a in li :
    print(a)

输出结果：

123
love
[‘a‘, 132, ‘abc‘]
我爱你
True

Process finished with exit code 0

 

2.列表元素是可以修改的

li = [123,"love",[‘a‘,132,‘abc‘],"我爱你",True]
li[0] = ‘cao‘
print(li)

运行结果：

[‘cao‘, ‘love‘, [‘a‘, 132, ‘abc‘], ‘我爱你‘, True]

Process finished with exit code 0

也可以通过切片的方式修改：

li = [123,"love",[‘a‘,132,‘abc‘],"我爱你",True]
li[0:3] = [‘cao‘,‘ni‘,‘ma‘]
print(li)

运行结果：

[‘cao‘, ‘ni‘, ‘ma‘, ‘我爱你‘, True]

Process finished with exit code 0

 

2.列表元素的删除

第一种方法：

li = [123,"love",[‘a‘,132,‘abc‘],"我爱你",True]
del li[0]
print(li)

运行结果：

[‘love‘, [‘a‘, 132, ‘abc‘], ‘我爱你‘, True]

Process finished with exit code 0

3.判断是否在列表里（嵌套的元素是一个整体）

li = [123,"love",[‘a‘,132,‘abc‘],"我爱你",True]
a = "abc" in li
print(a)

运行结果：

False

Process finished with exit code 0