一、列表和元组
列表是我们最常用到的数据类型之一，在一个变量中定义多个变量，可以理解为数组
定义列表
>>> name = ["liunx01","linux02","Unix",22] >>> print(name) [‘liunx01‘, ‘linux02‘, ‘Unix‘, 22] >>> name[0] ‘liunx01‘ >>> name[-1]
步长
>>> name [‘liunx01‘, ‘linux02‘, ‘Unix‘, 29, 22] >>> name[0::2] [‘liunx01‘, ‘Unix‘, 22]
切片，取多个元素
>>> name[0:1] [‘liunx01‘] >>> name[0:2] [‘liunx01‘, ‘linux02‘] >>> name[-3:-1] [‘linux02‘, ‘Unix‘] >>> name[-3:] [‘linux02‘, ‘Unix‘, 22] >>> name[:3] [‘liunx01‘, ‘linux02‘, ‘Unix‘] >>> name[:3][:2] [‘liunx01‘, ‘linux02‘]
追加
>>> name.append("CentOS")
>>> name
[‘liunx01‘, ‘Unix‘, 22,‘CentOS‘]
插入
>>> name.insert(2,‘RetHat‘) >>> name [‘liunx01‘, ‘Unix‘,‘RetHat‘,22,‘CentOS‘]
修改
>>> name[1] = "CentOS" >>> name [‘liunx01‘, ‘CentOS‘, ‘RetHat‘, 22,‘CentOS‘]
删除
>>> name
[‘liunx01‘, ‘CentOS‘, ‘RetHat‘, ‘Unix‘, 22]
>>> name.remove("RetHat") #指定元素删除
>>> del name[0:2] #切片删除
>>> name.pop() #删除最后一个value
>>> name
[‘Unix‘]
扩展
>>> name [‘liunx01‘, ‘CentOS‘, ‘RetHat‘, ‘Unix‘, 22] >>> b = [1,2,3] >>> name.extend(b) >>> name [‘liunx01‘, ‘CentOS‘, ‘RetHat‘, ‘Unix‘, 22, 1, 2, 3]
统计
>>> num = name.count(22) >>> print(num) 1
倒序、排序
>>> name = [22,"linux01","linux02","Unix",22] >>> name.reverse() >>> print(name) [22, ‘Unix‘, ‘linux02‘, ‘linux01‘, 22] >>> name = [22,"linux01","linux02","Unix",22] >>> name.sort() #注意3.0里面字符串和数字不能直接排序，用2.0 >>> print(name) [22, 22, ‘Unix‘, ‘linux01‘, ‘linux02‘]
找索引位置
name = [22,"linux01","linux02","Unix",22] for i in range(name.count(22)): ele_index = name.index(22) name[ele_index] = 999 print(name)
判断列表中是否存在一个元素
>>> name [‘liunx01‘, ‘linux02‘, ‘Unix‘, 29, 22] >>> print(2 in name) False >>> print(22 in name) True
拷贝
>>> name [‘liunx01‘, ‘CentOS‘, ‘RetHat‘, ‘Unix‘, 22] >>> name_copy = name.copy() >>> name_copy [‘liunx01‘, ‘CentOS‘, ‘RetHat‘, ‘Unix‘, 22]
列表的拷贝可不止上面那么简单：
共享列表第二层内存地址
import copy name = [22,"linux01","linux02",[88,87,86],"Unix",22] name3 = name.copy() #拷贝列表 name4 = copy.copy(name) #浅copy（软链接） name5 = copy.deepcopy(name) #深copy（完全拷贝） name[0] = 100 name[3][2] = 100 print(name) print(name3) print(name4) print(name5) #输出 [100, ‘linux01‘, ‘linux02‘, [88, 87, 100], ‘Unix‘, 22] [22, ‘linux01‘, ‘linux02‘, [88, 87, 100], ‘Unix‘, 22] [22, ‘linux01‘, ‘linux02‘, [88, 87, 100], ‘Unix‘, 22] [22, ‘linux01‘, ‘linux02‘, [88, 87, 86], ‘Unix‘, 22]
元组
元组其实跟列表差不多，也是存一组数，只不是它一旦创建，便不能再修改，所以又叫只读列表
names = ("alex","jack","eric")
它只有2个方法，一个是count,一个是index
字符串操作
n_arg = {‘name‘:‘lichengbing‘,‘age‘:25}n = ‘My name is {name} and age is {age}‘
print(n.format_map(n_arg))
My name is lichengbing and age is 25
n1 = ‘Hello World‘
print(n1.ljust(40,"-"))
Hello World-----------------------------
n1 = ‘Hello World‘
print(n1.rjust(40,"-"))
-----------------------------Hello World
s = "Hello World!"p = str.maketrans("abcdefg","[email protected]#$%^")
print(s.translate(p))
H$llo Worl#!
b="ddefdsdff_哈哈"
print(b.isidentifier()) #检测一段字符串可否被当作标志符，即是否符合变量命名规则
True
字典
由于列表中嵌套列表的做法不便于我们取值，所以就有了字典
字典的特性：key-value、dict是无序的、key值必须唯一
字典的定义
id_db = {
100: {
‘name‘:"linux",
‘age‘:24,
‘addr‘:"shanghai"
},
101: {
‘name‘:"nuix",
‘age‘:23,
‘addr‘:"anhui",
},
}
输出
{100: {‘age‘: 24, ‘name‘: ‘linux‘, ‘addr‘: ‘shanghai‘},
101: {‘age‘: 23, ‘name‘: ‘nuix‘, ‘addr‘: ‘anhui‘}}
增加（或者覆盖）
dict2 = {
‘name‘: "Redhat",
103: {
‘name‘:"Ubuntu",
},
}
id_db.update(dict2)
print(id_db)
{‘name‘: ‘Redhat‘, 100: {‘age‘: 24, ‘name‘: ‘linux‘, ‘addr‘: ‘shanghai‘},
101: {‘age‘: 23, ‘name‘: ‘nuix‘, ‘addr‘: ‘anhui‘}, 103: {‘name‘: ‘Ubuntu‘}}
删除
del id_db[101] #删除整个value里面的数据
id_db[101].pop("addr") #删除单个数据
获取get
v = id_db.get(102) print(v)
获取值或者key
print(id_db.values()) print(id_db.keys())
dict_values([{‘name‘: ‘linux‘, ‘addr‘: ‘shanghai‘, ‘age‘: 24},
{‘name‘: ‘nuix‘, ‘addr‘: ‘anhui‘, ‘age‘: 23}])
dict_keys([100, 101])
字典转列表
print(id_db.items())
dict_items([(100, {‘name‘: ‘linux‘, ‘addr‘: ‘shanghai‘, ‘age‘: 24}),
(101, {‘name‘: ‘nuix‘, ‘addr‘: ‘anhui‘, ‘age‘: 23})])
判断包含
id_db.has_key(185185) #only in 2.x
if 185185 in id_db:
print("yes")
else:
print("no")
setdefault
print(id_db.setdefault(185,"9999")) #取一个值，如果值不存在则新添加一个默认值
print(id_db)
9999
{185: ‘9999‘, 100: {‘addr‘: ‘shanghai‘, ‘age‘: 24, ‘name‘: ‘linux‘},
101: {‘addr‘: ‘anhui‘, ‘age‘: 23, ‘name‘: ‘nuix‘}}
fromkeys
print(id_db.fromkeys([1,2,3,56],‘dddd‘)) #设置一个新字典，前面是key后面填充value
print(id_db)
{56: ‘dddd‘, 1: ‘dddd‘, 2: ‘dddd‘, 3: ‘dddd‘}
{100: {‘name‘: ‘linux‘, ‘addr‘: ‘shanghai‘, ‘age‘: 24},
101: {‘name‘: ‘nuix‘, ‘addr‘: ‘anhui‘, ‘age‘: 23}}
popitem
print(id_db.popitem()) #随机删除一个key，不要用这个随机删除
(100, {‘name‘: ‘linux‘, ‘age‘: 24, ‘addr‘: ‘shanghai‘})
循环
‘‘‘ for k,v in id_db.items(): #循环效率低，因为有一个dict转list的过程 print(k,v) ‘‘‘ for key in id_db: #效率高 print(key,id_db[key])
set集合
set集合是一个无序且不重复的元素集合
1）创建集合
se1 = {11,22}
print(type(se1))
se2 = set([22,33])
print(se2)
输出
<class ‘set‘>
{33, 22}
2）操作集合
集合操作方法和前面的字符串、字典等类似
增加
#se1.add(44)
A存在B不存在
#se3 = se1.difference(se2)
A有B无 B有A无
#se4 = se1.symmetric_difference(se2)
更新se1
# se1.difference_update(se2)
移除(不存在不报错)
#se1.discard(11)
remove（不存在报错）
#se1.remove(11)
随机移除(返回移除的元素,这里pop里面不能加参数，而list里面pop可以有参数)
#ret = se1.pop()
交集
#se5 = se1.intersection(se2)
合并并集
#se6 = se1.union(se2)
update(接受一个可以被迭代的对象)
# lii = [11,2,3] # se8 = se1.update(lii) 不能以这种形式来更新 se1.update(lii) se7 = se1 print(se7)
小程序练习
题目：资产盘点结果中，找出CMDB项目中哪些要增加、哪些要被删除、哪些要更新。
这里以两个字典示范
old_dict = {
"#1": 8,
"#2": 4,
"#4": 2,
}
new_dict = {
"#1": 4,
"#2": 4,
"#3": 2,
}
set_old = set(old_dict)
set_new = set(new_dict)
set_del = set_old.difference(set_new)
set_add = set_new.difference(set_old)
set_update = set_old.intersection(set_new)
时间： 2024-10-14 05:28:41