python-基础列表集合字典文件处理

Posted 2020-08-19

tags:

篇首语：本文由小常识网(cha138.com)小编为大家整理，主要介绍了python-基础列表集合字典文件处理相关的知识，希望对你有一定的参考价值。

列表、元组操作
字典操作
集合操作
文件操作

1.列表、元组操作

　列表是最常用的数据类型之一，通过列表可以对数据实现最方便的存储、修改等操作

定义列表

names = ["张三","李四","王麻子"]

通过下标取列表中的数据.下标按0开始计算

names = ["张三","李四","王麻子"]
print(names[0])
张三
print(names[1])
李四
print(names[2])
王麻子
注意:也可以倒着取
print(names[-3])
张三
print(names[-2])
李四
print(names[-1])
王麻子

切片:取多个元素(顾头不顾尾.不取尾)

names = ["张三","李四","王麻子","疯子","傻子"]
print(names[0:2])
[‘张三‘, ‘李四‘]
print(names[:3])
[‘张三‘, ‘李四‘, ‘王麻子‘]
print(names[1:])
[‘李四‘, ‘王麻子‘, ‘疯子‘, ‘傻子‘]
print(names[0::2])
[‘张三‘, ‘王麻子‘, ‘傻子‘]
print(names[::2])
[‘张三‘, ‘王麻子‘, ‘傻子‘]

追加(在最后一位增加)

names = ["张三","李四","王麻子","疯子","傻子"]
names.append("SB")
print(names)<br>[‘张三‘, ‘李四‘, ‘王麻子‘, ‘疯子‘, ‘傻子‘, ‘SB‘]

插入(随便在什么地方插入)

names = ["张三","李四","王麻子","疯子","傻子"]
names.insert(2,"老寒腿")
names.insert(5,"大脚")
print(names)
[‘张三‘, ‘李四‘, ‘老寒腿‘, ‘王麻子‘, ‘疯子‘, ‘大脚‘, ‘傻子‘, ‘SB‘]

修改

names = ["张三","李四","王麻子","疯子","傻子"]
names[2] = ("麻子")
print(names)
[‘张三‘, ‘李四‘, ‘麻子‘, ‘疯子‘, ‘傻子‘]

删除

#指定删除下标对应的
names = ["张三","李四","王麻子","疯子","傻子"]
del  names[4]
print(names)
[‘张三‘, ‘李四‘, ‘王麻子‘, ‘疯子‘]
 
#使用remove删除时只能删除第一个出现的
names = ["张三","李四","李四","王麻子","疯子","傻子"]
names.remove("李四")
print(names)
[‘张三‘, ‘李四‘, ‘王麻子‘, ‘疯子‘, ‘傻子‘]
 
#使用pop删除时删除列表中的最后一个值
names = ["张三","李四","李四","王麻子","疯子","傻子"]
names.pop()
print(names)
[‘张三‘, ‘李四‘, ‘李四‘, ‘王麻子‘, ‘疯子‘]

拷贝(此处的拷贝是浅拷贝.意思是只拷贝第一层)

names = ["张三","李四","李四","王麻子","疯子","傻子"]
names_copy = names.copy()
print(names_copy)
[‘张三‘, ‘李四‘, ‘李四‘, ‘王麻子‘, ‘疯子‘, ‘傻子‘]

统计

names = ["张三","李四","李四","王麻子","疯子","傻子"]
print("李四出现次数:",names.count("李四"))
李四出现次数: 2

排序

names = ["张三","李四","李四","王麻子","疯子","傻子","3","2"]
names.sort()
print(names)
[‘2‘, ‘3‘, ‘傻子‘, ‘张三‘, ‘李四‘, ‘李四‘, ‘王麻子‘, ‘疯子‘]

#3.0里不同数据类型不能放在一起排序了

获取下标

names = ["张三","李四","李四","王麻子","疯子","傻子","1","3","2"]
print("李四的下标是:",names.index("李四"))
李四的下标是: 1　　　　<br>#只返回找到的第一个下标

2.字典操作

字典一种key - value的数据类型。

K怎么定义调用的时候就得怎么调用。

key 定义规则：1.不可变：数字，字符串，元组（可变：列表，字典）。K 唯一(如果K定义重复那么取的时候只取最后一次出现的)
v 定义规则：任意类型
字典：定义符号（），与列表完全一致，唯一不同的是元组内元素不可变
语法:

dic = {name:"Yuhl",age=18,QQ=2878****}
特性：无序
     Key必须唯一.

增加

dic = {"name":"Yuhl","age":"18","QQ":"2878****"}
dic["Phone"] = "110"
print(dic)　　　　　　　　　　　　　　　#增加
 
{‘Phone‘: ‘110‘, ‘age‘: ‘18‘, ‘QQ‘: ‘2878****‘, ‘name‘: ‘Yuhl‘}
 
dic00 = {"name":{"Yuhl":{"age","QQ"},"QQ":"111"},"age":18}
dic00.setdefault("gender","zhang")　#增加，随机
print(dic00)

修改

dic = {"name":"Yuhl","age":"18","QQ":"2878****"}
dic ["name"] = "Yuhonglin"
print(dic)      　　　　　　　　　　　　　　　　　　　　 注意:K值无法进行修改.只能修改value
{‘QQ‘: ‘2878****‘, ‘age‘: ‘18‘, ‘name‘: ‘Yuhonglin‘}
 
dic00 = {"name":{"Yuhl":{"age","QQ"},"QQ":"111"},"age":18}
dic00.update(name="YUHONGLIN",gender="name") 　　　　#修改和新增
print(dic00)
{‘age‘: 18, ‘gender‘: ‘name‘, ‘name‘: ‘YUHONGLIN‘}

删除

#删除
dic = {"name":"Yuhl","age":"18","QQ":"2878****"}
del dic["name"]
print(dic)
 
{‘QQ‘: ‘2878****‘, ‘age‘: ‘18‘}
#标准删除
dic = {"name":"Yuhl","age":"18","QQ":"2878****"}
dic.pop("name")
print(dic)
 
{‘age‘: ‘18‘, ‘QQ‘: ‘2878****‘}
#随机删除
dic = {"name":"Yuhl","age":"18","QQ":"2878****"}
dic.popitem()
print(dic)　　多试几次有效果

查找

dic = {"name":"Yuhl","age":"18","QQ":"2878****"}
print("打印结果是:",dic.get("name"))       #获取
 
打印结果是:Yuhl      
dic = {"name":"Yuhl","age":"18","QQ":"2878****"}
print("打印结果是:",dic["name"])           #与之前的一样
 
打印结果是:Yuhl
dic = {"name":"Yuhl","age":"18","QQ":"2878****"}
print("打印结果是:","stu1102" in dic)
 
打印结果是:False                            #在字典中有返回True否则返回False
 
 
dic = {"name":"Yuhl","age":"18","QQ":"2878****"}
print("打印结果是:",dic["stu1105"])         #如果一个key不存在会报错. get不会直接返回None

其他方法:

dic00 = {"name":"Yuhl","age":18}
dic00.clear()         #清空
print(dic00)
答应出来的信息是:{}
 
dic00 = {"name":{"Yuhl":{"age","QQ"},"QQ":"111"},"age":18}
dic000002= dic00.fromkeys(["a","b"],1)        #快速生成字典
print(dic000002)
 
自动生成的字典是: {‘b‘: 1, ‘a‘: 1}  
 
dic00 = {"name":{"Yuhl":{"age","QQ"},"QQ":"111"},"age":18}
for k,v in dic00.items():
    print(k,v)                  #列表打印
    print(k[0],v)              #列表打印
 
dic000 = {"name":"Yuhl","age":18,"QQanddianhua":[110,133]}
dic00new = dic000.copy() 　　　　　　　　　　　　　　　　#拷贝.浅拷贝
print(dic00new,"\n",dic000)
 
dic00 = {"name":{"Yuhl":{"age","QQ"},"QQ":"111"},"age":18}　　
dic00["QQanddianhua"]="11222","111111"　　　　　　　　#拷贝
print("\n",dic00)
{‘age‘: 18, ‘QQanddianhua‘: (‘11222‘, ‘111111‘), ‘name‘: {‘QQ‘: ‘111‘, ‘Yuhl‘: {‘age‘, ‘QQ‘}}}

3、集合

作用:去重复和关系运算(集合分别有:交集、差集、并集)其他方法:

#交集

python_set = {"alex","lhf","zhangsan","lisi","wangmazi"}
linux_set = {"alex","lhf","Yuhl","dsd"}
print(python_set&linux_set)             #求两个集合里面出现相同的数
print(python_set.intersection(linux_set))
print(python_set&linux_set)
print(python_set.intersection(linux_set))
　　：{‘lhf‘, ‘alex‘}
　　：{‘lhf‘, ‘alex‘}
　　：{‘lhf‘, ‘alex‘}
　　：{‘lhf‘, ‘alex‘}
python_set = {"alex","lhf","zhangsan","lisi","wangmazi"}
linux_set = {"alex","lhf","Yuhl","dsd"}<br>
#并集
print(python_set|linux_set) 　　　　#去重复
print(python_set.union(linux_set)) #去重复
　　：{‘lhf‘, ‘Yuhl‘, ‘dsd‘, ‘alex‘, ‘wangmazi‘, ‘lisi‘, ‘zhangsan‘}
　　：{‘lhf‘, ‘Yuhl‘, ‘dsd‘, ‘alex‘, ‘wangmazi‘, ‘lisi‘, ‘zhangsan‘}
 
  
 
# #差集
python_set = {"alex","lhf","zhangsan","lisi","wangmazi"}
linux_set = {"alex","lhf","Yuhl","dsd"}
print(python_set-linux_set) #去掉重复的
print(python_set.difference(linux_set))
print(linux_set-python_set) #去掉重复的
print(linux_set.difference(python_set))
{‘lisi‘, ‘zhangsan‘, ‘wangmazi‘}
{‘dsd‘, ‘Yuhl‘}
 
#并集
python_set = {"alex","lhf","zhangsan","lisi","wangmazi"}
linux_set = {"alex","lhf","Yuhl","dsd"}
print(python_set|linux_set)        #去重复(将两个重复数据打印出来.合并在一起)
print(python_set.union(linux_set)) #去重复(将两个重复数据打印出来.合并在一起)
  
#d对称差集
python_set = {"alex","lhf","zhangsan","lisi","wangmazi"}
linux_set = {"alex","lhf","Yuhl","dsd"}
print(python_set^linux_set)#把共有的地方去掉就是对称差集
print(python_set.symmetric_difference(linux_set))
　：{‘lisi‘, ‘dsd‘, ‘zhangsan‘, ‘wangmazi‘, ‘Yuhl‘}
　：{‘lisi‘, ‘dsd‘, ‘zhangsan‘, ‘wangmazi‘, ‘Yuhl‘}
 
  
 
s1 = {1,2,3,4,5}
s2 = {2,3}
#子集
print(s1 <= s2) #s2是s1的子集
print(s1.issubset(s2))
 
#父集
print(s2 <= s1) #s1是s2的父集
print(s1.issuperset(s2))
 
s3 = set(["he","l","1","1",1,2,3])
print(s3)

其他方法:

#更新
s1 = {1,2,3}
s2 ={"YHL"}
s1.update(‘e‘)          #插入
s1.update((1,2,3,4,5))   #去重进行写入
s1.update("hello")
s1.update(s2)
print(s1)
  
  
#增加
s1 = {1,2,3}
s1.add("Hello")     #整个加入
print(s1)
  
  
#删除
s3 = {1,2,3,4,5,6,7,8,9,10}
s3.pop()
print(s3)   　　　　　　  #随机删除
s3.remove(10) 　　　　　　#指定删除  如果没有会报错
print(s3)
s3.discard("a")     　　 #不报错的删除  没有也不会报错.有不会报错
print(s3,"------")

4.文件处理

以上是关于python-基础列表集合字典文件处理的主要内容，如果未能解决你的问题，请参考以下文章

Python基础数据类型（数字字符串布尔列表元组字典集合等）

python-基础列表集合字典

Python基础2 列表字典集合

python 3 基础之各种推导式（列表字典集合）

python基础之列表元组操作字符串操作字典操作集合操作文件操作字符编码与转码

python基础巩固（变量类型：字典集合元组列表数字字符串）

python-基础 列表 集合 字典 文件处理

3、集合

4.文件处理

python-基础列表集合字典文件处理