一、计数器
print("请选择算法运算符")
print('''
1、加
2、减
3、乘
4、除
''')
choice = input("请输入标号!")
num1 = int(input("请输入第一个数字"))
num2 = int(input("请输入第二个数字"))
if choice == '1':
print(num1 + num2)
elif choice == '2':
print(num1 - num2)
elif choice == '3':
print(num1 * num2)
elif choice == '4':
print(num1 / num2)
else:
print("输入有误!!")
二、列表
computer = ["主机","显示器","鼠标","键盘"]
print(computer.index("主机"))
print(computer.count("显示器"))
computer.reverse()
print(computer)
computer.sort()
print(computer)
computer.append("u盘")
print(computer)
computer.insert(1,"耳机")
print(computer)
computer[1] = "蓝牙耳机"
print(computer)
computer.remove("蓝牙耳机")
print(computer)
print(computer[1:3])
computer = []
del computer
三、元组(元组与列表的差异在于元组中的元素不能修改)
computer = ("主机","显示器","鼠标","键盘")
print(computer.index("主机"))
print(computer.count("主机"))
print(computer[1:3])
四、集合(set)是无序,不重复,定义方法 set()函数或者大括号
computer = {"主机","显示器","鼠标","键盘"}
computer = set(["主机","显示器","鼠标","键盘"])
#列表去重
computer = ["主机","显示器","鼠标","键盘","主机","显示器"]
s= set(computer)
print(s)
s.add("耳机")
s.remove("显示器")
s.discard("蓝牙耳机")
a = set([1,2,3,4,5,6])
b = set([4,5,6,7,8,9])
print(a - b)
print(a & b)
print(a | b)
print(a != b)
五、字典 字段 key不重复
computer = {"主机":5000,"显示器":1000,"鼠标":500}
print(computer["主机"])
print(computer.get("主机",None))
print(computer.keys())
print(computer.values())
print(computer.items())
六、分支
age = int(input("请输入你的年龄"))
if age <= 7:
print("儿童")
elif age > 7 and age < 18
print("少年")
elif age >=18 and age < 65
print("中年")
else
print("老年")
七、循环
for n in range(1,5):
print("第%s次种花" %n)
s = "123456"
for i in s:
print(i)
computer = ["主机","显示器","鼠标","键盘"]
for i in computer:
print(i,len(i))
computer = {"主机":5000,"显示器":1000,"鼠标":500}
for i in computer.items():
print(i[0],i[1])
count = 0
while count <= 5:
print(count)
count += 1
for n in range(1,6):
if n == 3:
continue
else:
print(n)
for n in range(1,6):
if n == 3:
break
else:
print(n)
count = 0
while 1:
if count < 3:
name = input("请输入用户名").strip()
if(len(name) == 0):
print("输入不能为空")
continue
elif(name == 'xiaoming'):
print("登录成功")
break
else:
print("输入有误,重新输入")
count += 1
else:
print("超过错误次数")
break
八、文件操作
f = open("user.txt",'w+')
print(f.readline())
print(f.read())
f.write("zhaoliu 777777 guangdong")
f.flush()
f.close()
f = open('computer.txt')
for line in f:
print(line)
f.close()
#异常与否,with执行完后关闭句柄
with open('computer.txt',encoding="utf8") as f:
data = f.read()
print(data)
九、函数
def hello():
print("Hello world!")
hello()
def sum(a,b=2):
return a + b
print(sum(b=3,a=4))
def seq(n):
result = []
x = 0
while x <= n:
result.append(x)
x += 1
return result
print(seq(9))
# *args 接受任意到元组 **kwargs 接受健值到字典
def sum2(*seq):
x = 0
for n in seq:
x += n
return x
print(sum2(1,2,3))
def func(**computer):
for k,v in computer.items():
print("name:%s,price:%s" % (k,v))
print(func(zhuji=100,erji=200))
s = lambda a,b:a+b
print(s(3,4))