python基础知识笔记（1）

 print("hello,world")

    
 age=18
    
 print("我的年龄是%d岁,我叫%s"%(age,"小白"))

 a=input("请输入a= ")

    
 b=input("请输入b= ")
    
 if a>=b :
    
     print("yes yes yes")
    
 else:
    
     print("no no no")

  
    
 for i in [1,2,3,4,5,6]:
    
     print(i)
    
  
    
 for i in range(5):
    
     print(i)
    
  
    
 for i in range(1,10,2):
    
     print(i)
    
  
    
 st="hello world"
    
 for i in st:
    
     print(i)
    
  
    
 lb=[6,66,666,"你","好"]
    
 for i in lb:
    
     print(i)
    
  
    
 tup=(2,233,"hello")
    
 for i in tup:
    
     print(i)
    
  
    
 dict={"name":"小白","age":18}
    
 for i in dict:
    
     print (i,dict[i])

 sum=0

    
 i=1
    
 while i<101:
    
     sum=sum+i
    
     i+=1
    
 print(sum)
    
  
    
 sum=0
    
 for i in  range(101):
    
     sum=sum+i
    
 print(sum)

 lb=[6,66,666,"你","好"]

    
 tup=(6,66,666,"你","好")
    
 dict={"name":"小白","age":18}
    
  
    
 ###增###
    
 #1.列表
    
 #1.1 append-整体添加
    
 a=["a","aa",1,11]
    
 lb.append(a)
    
 print (lb)             #[6, 66, 666, '你', '好', ['a', 'aa', 1, 11]]
    
  
    
 #1.2 extend-逐一添加
    
 a=["a","aa",1,11]
    
 lb.extend(a)
    
 print(lb)              #[6, 66, 666, '你', '好', 'a', 'aa', 1, 11]
    
  
    
 #1.3 insert-指定位置插入
    
 lb.insert(3,"insert")
    
 print(lb)
    
  
    
 #2.元组-元组的元素不能修改
    
 tup1=("a","aa","1","11",[1,11])
    
 print(type(tup1))
    
 tup2=tup+tup1
    
 print(tup2)             #(6, 66, 666, '你', '好', 'a', 'aa', '1', '11', [1, 11])
    
  
    
 #3.字典
    
 #直接在后面插入
    
 dict["id"]=1314 
    
 print(dict)             #{'name': '小白', 'age': 18, 'id': 1314}

  
    
 lb=[6,66,666,"你","好"]
    
 tup=(6,66,666,"你","好")
    
 dict={"name":"小白","age":18}
    
  
    
 ###删###
    
 #1.列表
    
 #1.1 del
    
 del lb[2]
    
 print(lb)        #[6, 66, '你', '好']
    
 del lb
    
 print(lb)  #NameError: name 'lb' is not defined
    
 #1.2 pop
    
 lb.pop()
    
 print(lb)        #[6, 66, 666, '你']  删除最后一个
    
 #1.3 remove
    
 lb.remove("你")
    
 print(lb)        #[6, 66, 666, '好']   删除指定元素
    
  
    
 #2.元组-元组的元素不能修改
    
 del tup
    
 print(tup)        #NameError: name 'tup' is not defined
    
  
    
 #3.字典
    
 del dict["name"]
    
 print(dict)        #{'age': 18}

 lb=[6,66,666,"你","好"]

    
 tup=(6,66,666,"你","好")
    
 dict={"name":"小白","age":18}
    
  
    
 ###改###
    
 #1列表
    
 lb[2]="修改"
    
 print(lb)           #[6, 66, '修改', '你', '好']
    
  
    
 #2元组元素不能修改
    
  
    
 #3字典
    
 dict["name"]="小黑"
    
 print(dict)         #{'name': '小黑', 'age': 18}

 lb=[6,66,666,"你","好"]

    
 tup=(6,66,666,"你","好")
    
 dict={"name":"小白","age":18}
    
  
    
 #1 列表
    
 #1.1 用if  else 查找in   or  not in
    
 if "你" in lb:
    
     print("yes")
    
 else:
    
     print("no")
    
 #1.2 index 左闭右开
    
 print(lb.index("你",0,4))  #3
    
 #1.3 count 查询有几个要查找的元素
    
 print(lb.count("你"))      #1
    
 #1.4 reverse
    
 lb.reverse()
    
 print(lb)                  #['好', '你', 666, 66, 6]
    
 #1.5 sort
    
 lb1=[6,66,666,11,111]
    
 lb1.sort()
    
 print(lb1)                 #[6, 11, 66, 111, 666]
    
 lb1.sort(reverse=True)
    
 print(lb1)                 #[666, 111, 66, 11, 6]
    
  
    
 #2元组
    
 print(tup)
    
 print(tup[1])               #66
    
 print(tup[0:2])             #(6, 66)
    
  
    
 #字典
    
 print(dict)
    
 print(dict["name"])         #小白
    
 print(dict.get("gender"))   #None
    
 print(dict.get("gender","查找不到时，自定义返回"))  #查找不到时，自定义返回
    
 print(dict.keys())          #dict_keys(['name', 'age'])
    
 print(dict.values())        #dict_values(['小白', 18])
    
 print(dict.items())         #dict_items([('name', '小白'), ('age', 18)])
    
 for X,Y in dict.items():
    
     print("%s：%s"%(X,Y),end="\t")    
    
                         #name：小白	age：18

 #1 函数定义

    
 def python ():
    
     print("--"*30)
    
     print("life is short,use python")
    
     print("--" * 30)
    
 python()
    
  
    
 #2 带参数、返回值的函数
    
 def addnum(a,b):
    
     return  a+b
    
 print(addnum(100,1))
    
  
    
 #3 返回多个值得函数
    
 def divide(a,b):
    
     shang=a//b
    
     yushu=a%b
    
     cha=a-b
    
     return shang,yushu,cha
    
 shang,yushu,cha=divide(7,2)
    
 print("%d %d %d"%(shang,yushu,cha))