注释

单行注释 # 多行注释 """ """

数据类型

t=type(x)

强制类型转换

a=float(a)
print(a3[-1],a3[2:6])   //不包括最后一位

print(a3[0:-1],a3[:-1],a3[1:])

print(a3[2:7:2]) # low:hight:step
a3.append(10)
a7=list(a6.keys())

int

a1=1

str

a2='123'

list

a3=[1,2,3]

tuple

a4=(1,2,3)

dict

a6={"js":"nj","zj":"hz","ah":"hf"} 

key:val

逻辑运算

and //not &&
or //not ||
2 in a3

'2' in a2

IO

print(x)
print("sum1:{};sum2:{}".format(a1,a2))
score=eval(input("输入成绩："))
print(a6['zj'],a6.get('zj'))

print(a6.get('jx')) #a6['jx'],  //若没有a6,get返回空，#a6['jx']报错

循环&&条件判别

x=range(1,100)#不包括100
print(x)
lx=list(x)

print(lx)
sx="abcdefg"
for i in sx:

print(i)
sum=0

for i in x:

sum+=i;

print(sum)    
len(sx)=>8
range(len(sx))=>range(8)=>[0,1,2,3,...]
for i in range(len(sx)):

print(sx[i])
i=0

while i<len(sx):

print(sx[i])

i+=1
score=eval(input("输入成绩："))

if score==100:

print("满分")

elif score>=90:

print("优秀")

elif score>=80:

print("良好")

elif score>=60:

print("及格")

else :

print("不及格")