Python列表

列表用[]表示，列表是一个值，这个值可以传递函数

1.通过列表下标访问列表的值

a = ['1','2',3,4,['a','b']]

print(a[0])
print(a[1])
print(a[2])
print(a[3])
print(a[4])

2.负数下标

a = ['1','2',3,4,['a','b']]

print(a[-1],a[-2],a[-3],a[-4],a[-5])

3.切片

注意最后一个不包含

a = ['1','2',3,4,['a','b']]

print(a[1:])
print(a[1:4])

5.len获取长度

a = ['1','2',3,4,['a','b']]

print(len(a))

6.修改值

a = ['1','2',3,4,['a','b']]

a[1] = 2
print(a[1:4])

7.列表的连接与复制

a = ['1','2',3,4,['a','b']]

a = a + [5,6]
print(a)

8.del语句从列表中删除

a = ['1','2',3,4,['a','b']]

del a[1]
print(a)

9.列表与for循环的结合

a = [0,1,2,3]

for i in a :
    print(i)

10.列表的常用方法

• 返回下标index()

a = [0,1,2,3]

print(a.index(0))
print(a.index(1))
print(a.index(2))
print(a.index(3))

• append()和insert()

a = [0,1,2,3]


a.append(5)
a.append(6)

print(a)

a = [0,1,2,3]


a.insert('5',4)
a.insert('6',5)

print(a)

• remove

a = [0,1,2,3,1]

a.remove(1)
print(a)

• sort

顺序

a = ['q','w','w','w','r','t']
# 按照ASCLL码排序
a.sort()
print(a)

逆序

a = ['q','w','w','w','r','t']

a.sort(reverse = True)
print(a)