Python学习（四）列表与列表操作

读取列表

列表：由一系列按特定顺序排列的元素组合。Python中使用“[]”表示列表

bicycles = ['trek','cannondale','redline','specialized']

#读取所有列表

print(bicycles)

['trek', 'cannondale', 'redline', 'specialized']

#读取指定列表

print(bicycles[0])

trek

#读取指定列表,指定单词首字母大写

print(bicycles[0].title())

Trek

列表操作

列表命名规则：name = []
列表下标：[0,1,2,3....] 或 [...-3,-2,-1]

names = ["zhangsan","lisi","wangwu","maliu"]

查询列表

#显示列表

print(names)

['zhangsan', 'lisi', 'wangwu', 'maliu']

#取下标“0”的值===切片

print(names[0])

zhangsan

#连续的正向取值,"1,2,3"，取值规则顾头不顾尾,顺序左到右===切片

print(names[1:4])

['lisi', 'wangwu', 'maliu']

#连续的逆向取值，“-2，-1”===切片

print(names[-2:])

['wangwu', 'maliu']

#连续的逆向取值，“-2”顾头不顾尾===切片

print(names[-2:-1])

['wangwu']

#连续的逆向取值，“0,1,2”顾头不顾尾===切片

print(names[0:3])

print(names[:3])

['zhangsan', 'lisi', 'wangwu']

['zhangsan', 'lisi', 'wangwu']

#查询列表长度

print(len(names))

print(names)

4

['zhangsan', 'lisi', 'wangwu', 'maliu']

#查询参数的下标位

print(names.index("zhangsan"))

0

#统计参数个数

print(names.count("zhangsan"))

1

#反转列表

names.reverse()

print(names)

['maliu', 'wangwu', 'lisi', 'zhangsan']

#规则排序，特殊字符====数字===大写===小写

names.sort() print(names)

['lisi', 'maliu', 'wangwu', 'zhangsan']

#清空列表

print(names.clear())

增加列表

name = []

names = ["zhangsan","lisi","wangwu","maliu"]

# 追加参数

names.append("xiaoqi")

print(names)

['zhangsan', 'lisi', 'wangwu', 'maliu', 'xiaoqi']

# 指定位置增加参数

names.insert(1, "xiaoqi") print(names)

['zhangsan', 'xiaoqi', 'lisi', 'wangwu', 'maliu', 'xiaoqi']

# 列表扩展

names2 = ["123", "234"] names.extend(names2) print(names)

['zhangsan', 'xiaoqi', 'lisi', 'wangwu', 'maliu', 'xiaoqi', '123', '234']

删除列表

name = []

names = ["zhangsan","lisi","wangwu","maliu"]

print(names)

['zhangsan', 'lisi', 'wangwu', 'maliu']

# 替换指定参数

names[2] = "xiaoqi"

print(names)

['zhangsan', 'lisi', 'xiaoqi', 'maliu']

# 删除指定参数

names.remove("zhangsan")

print(names)

['lisi', 'xiaoqi', 'maliu']

# 默认删除最后一个，输入下标删除下标位

names.pop()

print(names)

['lisi', 'xiaoqi']

# 删除变量

names2 = ["123", "234"]

del names2

复制列表

#浅copy，仅复制第一层列表

names = ["zhangsan","lisi","wangwu","maliu"]

name2 = names.copy()

#完全复制一层列表

print(names)

['zhangsan', 'lisi', 'wangwu', 'maliu']

names[0] = "lili"

print(names)

['lili', 'lisi', 'wangwu', 'maliu']

print(name2)

['zhangsan', 'lisi', 'wangwu', 'maliu']

#浅copy，对第二层列表完全读取

names = ["zhangsan","lisi",["zhangsan","lisi"],"wangwu","maliu"]

name2 = names.copy()

#完全复制第一层列表

names [2][1] = "LLLL"

print(names)

["zhangsan","lisi",["zhangsan","LLLL"],"wangwu","maliu"]

print(name2)

["zhangsan","lisi",["zhangsan","LLLL"],"wangwu","maliu"]

copy模块

#深copy，完全克隆

import copy

names = ["zhangsan","lisi",["zhangsan","lisi"],"wangwu","maliu"]

name2 = copy.deepcopy(names)

#完全复制一层列表

names [2][1] = "LLLL"

print(names)

["zhangsan","lisi",["zhangsan","LLLL"],"wangwu","maliu"]

print(name2)

["zhangsan","lisi",["zhangsan","lisi"],"wangwu","maliu"]

列表循环

names = ["zhangsan", "lisi", "wangwu", "maliu","zhaoliu"]

# 步长切片

for i in names:
    print(i)
print(names[0:-1:2])
print(names[::2])

zhangsan

lisi

wangwu

maliu

zhaoliu

['zhangsan', 'wangwu']

['zhangsan', 'wangwu', 'zhaoliu']

创建数字列表

#创建2-11,步长为2的数字列表“numb”

numb = list(range (2,11,2))

print(numb)

[2, 4, 6, 8, 10]

数字列表简单计算

numb = list(range (0,10))

print(numb)

[0, 1, 2, 3, 4, 5, 6, 7, 8, 9]

#列表取最小值

print(min(numb))

0

#列表取最大值

print(max(numb))

9

#列表求和

print(sum(numb))

45