2-序列类型-列表list-序列操作

列表list

声明列表

data1 = []
# 列表可以由0个或多个成员组成，可以使用type来观察数据类型
print(data1, type(data1))        # [] <class 'list'>
 
data2 = ["小A", "小Y", "小H"]
print(data2, type(data2))        # ['小A', '小Y', '小H'] <class 'list'>
 
# 列表中的成员，可以是任意格式的数据
data3 = ["xiaoming", True, 16, "1334565678"]
print(data3, type(data3))        # ['xiaoming', True, 16, '1334565678'] <class 'list'>

索引取值

l = [10, 11, 12, 13, 14]
print(l[2], l[-3])  # 12 12
 
# 提取最后一个成员
print(l[-1])        # 14
 
# 提取第一个成员
print(l[0])         # 10

切片操作，左闭右开原则

l = [10, 11, 12, 13, 14]
print(l[2:5])         # [12, 13, 14]
 
print(l[-3:-1])       # [12, 13]
 
print(l[:3])          # [10, 11, 12]
print(l[1:])          # [11, 12, 13, 14]
print(l[:])           # [10, 11, 12, 13, 14]
 
print(l[-1:-3])       # []
print(l[-1:-3:-1])    # [14, 13]
print(l[::2])         # [10, 12, 14]

可以通过in来判断指定数据是否作为成员存在

data = ["xiaoming", "xiaohua", "xiaohong", "xiaocheng"]
target = "xiaoming"
print(target in data)       # True
print("xiaohei" in data)    # False

l1 = [1, 2, 3]
l2 = [4, 5, 6]
print(l1 + l2)   # [1, 2, 3, 4, 5, 6]
 
print(l2 * 3)    # [4, 5, 6, 4, 5, 6, 4, 5, 6]

解包，变量的数量必须和列表的成员一致，否则报错

data = ["xiaoming", "xiaohong"]
name1, name2 = data
print(name1)    # xiaoming
print(name2)    # xiaohong

修改列表指定索引的值

data = ["ming", "hong"]
data[1] = "小红"
print(data)     # ['ming', '小红']