Python数据类型最全知识总结

 str = 'zhangsan' str = "zhangsan" str = '''zhangsan''' # 可以实现换行 str = """zhangsan""" # 可以实现换行 str = r'zhangsan\n'  # r可以取消转移字符的功能

 find('str')      # 找不到为-1 index('str')     # 找不到报错 isalnum('str')   # 由字母或数字组成 isspace('str')   # 由空格组成 split('str')     # 分割之后是列表 rsplit('str',2)  # 当分割次数有限制时与split有区别 partition('str') # 分割之后是三元组 capitalize()     # 字符串首字母大写 title()          # 每个单词首字母大写 ljust()          # 左对齐加空格 

 str = '123456789‘ # 下标取值 str[0] # 1 str[-1] # 9 # 切片语法 m[start, end, step] str[1:3]    # 23 str[3:1]    # 空 str[0:]     # 123456789 str[:3]     # 123 str[::]     # 123456789 str[::-1]   # 987654321 str[0:4:1]  # 1234 str[0:4:2]  # 13 str[0:4:0]  # 报错 str[0:4:-1] # 空 str[4:0:-1] # 5432 str[-3:-1]    # 78 str[-1:-3]    # 空 str[-3:-1:-1] # 空 str[-3:-1:1]  # 78 str[-1:-3:-1] # 98 str[-1:-3:1]  # 空 

 chr(65)                # 编码转为字符 ord('我')              # 字符转为编码 'str'.encode('utf-8')  # 将字符串转编码 'str'.decode('utf-8')  # 将字符串转解码

 %s(字符串)、 %d(整形)、 %f(浮点型)、 %%(%)、 %x(十六进制)、 %X(十六进制) name = 'zhangsan' age = 18 print('姓名：', name, ',年龄：', age, sep='') print('姓名：%s,年龄：%d' %(name,age)) ―――――――――――――――― 版权声明：本文为CSDN博主「ProChick」的原创文章，遵循CC 4.0 BY-SA版权协议，转载请附上原文出处链接及本声明。 原文链接：https://blog.gaodaimna/qq_45747519/article/details/117379242

 # 默认 print('姓名{},年龄{}'.format('张三',18)) # 下标赋值 print('姓名{1},年龄{0}'.format(18,'张三')) # 变量名赋值 print('姓名{name},年龄{age}'.format(name='zhangsan',age=18)) # 列表赋值 list = ['zhangsan',18] print('姓名{},年龄{}'.format(*list)) # 字典赋值 dict = {"name":'zhangsan',"age":18} print('姓名{name},年龄{age}'.format(**dict)) 

 mylist = ['张三',18] mylist = list( ('zhangsan',18) ) # 将可迭代对象转化为列表

 list = [1,2,3] # 追加 list.append(4)     # [1,2,3,4] # 插入 list.insert(0,0)   # [0<p style="color:transparent">来源gao!daima.com搞$代!码网</p>,1,2,3,4]

 list = [1,2,3] # 修改指定位置元素 list[0] = 0    # [0,2,3] list[2] = 0    # [0,2,0]

 list = [1,2,3,4,5,6] # 删除最后一个 list.pop()         # [1,2,3,4,5] # 删除指定位置 list.pop(0)        # [2,3,4,5] # 删除指定元素 list.remove(2)     # [3,4,5] # 清空 list.clear()       # [] 

 list = [1, 2, 3, 2, 1] # 查找元素位置 list.index(1)    # 0 # 查找元素个数 list.count(1)    # 2

 list1 = [1,2,3] list2 = [4,5,6] # 合并 list1.extend(list2) # [1,2,3,4,5,6] print(list1+list2)  # [1,2,3,4,5,6]

 list = [2, 3, 1] # 正序 list.sort()                                 # [1,2,3] # 产生新对象并正序 new_list = sorted(list)                     # [1,2,3] # 倒序 list.sort(reverse=True)                     # [3,2,1] # 倒序 list.reverse()                              # [3,2,1] # 自定义排序规则(一般用于字典类型的比较) list = [ {'name':'zhangsan',age:18}, {'name':'lisi',age:20}, {'name':'wangwu',age:19} ] list.sort(key = lambda item : item['age']) 

 list = [1, 2, 3] # 是浅拷贝 new_list = list.copy() # [1, 2, 3]

 # 相当于二维数组 list = [[1,2],[3,4],[5,6]]

 list = [i for i in range(1,3)] # [1,2] list = [(i,j) for i in range(1,3) for j in range(1)] # [(1,0),(2,0)]

 # 表示多个元素 tuple = (1,2,'3') # 表示1个元素 tuple = (True,)

 tuple = (1,True,'3',True) tuple.index(0)    # 1 tuple.count(True) # 2

 tuple1 = (1,2) tuple2 = (True,False) print(tuple1+tuple2) # (1,2,True,False)

 student = {"name":'zhangsan',"age":20} 

 student = {"name":'zhangsan',"age":20} print(student["age"])          # 20 print(student["birth"])        # 报错 print(student.get("age"))      # 20 print(student.get("birth"))    # None print(student.get("birth",'2000-10-10'))    # 2000-10-10d # 获取所有Key print(student.keys())          # ['name','age'] # 获取所有Value print(student.values())        # ['zhangsan',20] # 获取所有Key-Value print(student.items())         # [('name':'zhangsan'),('age':20)] 

 student = {"name":'zhangsan',"age":20} student["name"] = 'lisi' print(student) # student = {"name":'lisi',"age":20} student["sex"] = '男' print(student) # student = {"name":'lisi',"age":20,"sex":'男'} 

 student = {"name":'zhangsan',"age":20} # 删除Key-Value，返回Value result = student.pop("name") print(student) # student = {"age":20} print(result)  # zhangsan # 删除Key-Value，返回Key-Value result = student.popitem("name") print(student) # student = {"age":20} print(result)  # ('name','zhangsan') # 清空 student.clear() print(result)  # {} 

 student = {"name":'zhangsan',"age":20} student_add = {"sex":'男'} student.update(student_add) print(student) # {"name":'zhangsan',"age":20,"sex":'男'} 

 student = {"name":'zhangsan',"age":20} student_reverse = {v:k for k,v in student.items()} print(student_reverse) # {"zhangsan":'name',"20":age} 

 # 有元素的集合 set = {1,'我',True} # 空集合 set()

 set = {1,'我',True} set.add('zhangsan') print(set)             # {1,'我',True,'zhangsan'} 

 set = {1,'我',True} # 随机删除一个元素 set.pop() print(set)             # {'我',True} # 删除指定元素 set.remove('True') print(set)             # {1,'我'} # 清空 set.clear() print(set)             # set() 

 set = {1,'我',True} # 两个集合合并后产生新的集合 new_set = set.union( {True,False} ) print(new_set)                       # {1,'我',True,False} # 将一个可迭代对象合并到原有集合中 set.update(['False']) print(set)                           # {1,'我',True,'False'} 

 set1 = {1,2,3} set2 = {3,4,5} # 差集 print(set1 - ste2)  # {1,2} print(set2 - ste1)  # {4,5} # 交集 print(set1 & ste2)  # {3} # 并集 print(set1 | ste2)  # {1,2,3,4,5} # 差并集 print(set1 ^ ste2)  # {1,2,4,5} 

 ----(将数据转化为字符串)---- import json list = ['name','age','city'] file = open('test.txt','w',encoding='utf8') file.write(repr(list))       # 第一种方式 file.write(str(list))        # 第二种方式 file.write(json.dumps(list)) # 第三种方式 json.dump(list,file)         # 第四种方式 file.close() 

 ----(将数据转化为二进制)---- import pickle list = ['name','age','city'] file = open('test.txt','wb',encoding='utf8') file.write(pickle.dumps(list)) # 第一种方式 pickle.dump(list,file)         # 第二种方式 file.close() 

 # test.txt ["name","age","city"]

 ----(将字符串转化为数据)---- import json file = open('test.txt','r',encoding='utf8') list1 = json.load(file)               # 第一种方式 print(list1) # ['name','age','city'] list2 = json.loads(file.read())       # 第二种方式 print(list2) # ['name','age','city'] file.close() 

 ----(将二进制转化为数据)---- import pickle file = open('test.txt','rb',encoding='utf8') list1 = pickle.loads(file.read())       # 第一种方式 print(list1) # ['name','age','city'] list2 = pickle.load(file)               # 第二种方式 print(list2) # ['name','age','city'] file.close()