python基础知识笔记（1）-CFANZ编程社区

1 打印我的年纪

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

2 条件语句

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

3 for while循环，不仅可以迭代整数序列，还可以迭代其他对象如字符串列表元组字典


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])

3.1利用循环写出1+2+3......+100

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)

4 增-list、tup、dict的增

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}

4 删-list、tup、dict的删


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}

5 改-list、tup、dict的改

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}

6 查-list、tup、dict的查

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

7 函数-把具有独立功能的代码块组织为小模块

#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))