if a1==a2:print('ok')

from random import randint
x=randint(0,300)
digit= int(input('please input a number between 0-300:'))
if digit==x:print('bingo!')
elif digit>x:print('too large, please try again')
else:print('too small, please try again')

s=0
j=1
while j<10:s=s+jj=j+1
print(s)  # 45

f='python'
for x in f:print(x)
#  输出 p yt h o  n

for i in range(5):print(i, end=',')
#0,1,2,3,4,

from random import randint
x=randint(0,300)
for cnt in range(3):digit= int(input('please input a number between 0-300:'))if digit==x:print('bingo!')elif digit>x:print('too large, please try again')else:print('too small, please try again')

# 创建列表
[i for i in range(10)]
Out[11]: [0, 1, 2, 3, 4, 5, 6, 7, 8, 9]
[i+1 for i in range(10) if i%2==0]
Out[12]: [1, 3, 5, 7, 9]
# 生成器
(i for i in range(10))
Out[13]: <generator object <genexpr> at 0x000001D6BA07FF48>

s=0
j=1
while True:s=s+jj=j+1if s>20:break
print('j={},sum={}'.format(j,s)) # j=7,sum=21

from math import sqrt
j=2
while j<=100:i=2k=int(sqrt(j))while i<=k:if j%i==0 : breaki=i+1if i>k:print(j,end=' ')j=j+1
# 用for
for i in range(2,10):flag=1k=int(sqrt(i))for j in range(2,k+1): # i=2, k=1,j会有问题        if i%j==0:flag=0break     if flag: # 不能j>k,跳出循环j不会+1, 比如i=7,j=2 break,跳出后仍是j=2,2>2不成立则不输出7,error, 因此引入flagprint(i,end=',')i=i+1  

from random import randint
x=randint(0,300)
go='y'
while go=='y':digit= int(input('please input a number between 0-300:'))if digit==x:print('bingo!')breakelif digit>x:print('too large, please try again')else:print('too small, please try again')print('input y if you want to continue')go=input()print(go)
else:print('goodbye!')

for i in range(1, 10, 2):if i % 5 == 0:print("Bingo!")break
else:print(i)   

def fun_name(x):'apply operation + to argument'return(x+x)
print(fun_name(2))  #4   

from math import sqrt
def isprime(x):if x==1:return Falsek=int(sqrt(x))for i in range(2,k+1):if x%i==0:return Falsereturn True
for i in range(2,20):if isprime(i):print(i,end=' ')

def fun(x=True): # 默认参数值为trueif x:print('x is a correct word')print('ok')
fun() # 没有参数则默认为True ,输出x is a correct word  okfun(False) # 有参数则按照这个参数来, 最后只输出ok

def f(x,y=True):if y:print(x,'and y both correct')print(x,'is ok')
f(68)  # 默认传给x
#68 and y both correct
#68 is ok
f(68,False)  # 只输出68 is okdef f(y=True, x):if y:print(x,'and y both correct')print(x, 'is ok')
f(False) # 报错! , False应该给x 还是y? 

def f(x,y):if y:print(x,'and y both correct')print(x,'is ok')
f(y=2, x=1)

def add1(x):return(x+x)
def add2(x):return(x+10)
print(add2(add1(3)))  # 16

def add1(x):return(x+x)
def add2(f,x):return(f(x))
print(add2(add1,10))  # 20

r= lambda x :x**2
print(r(5)) #25
r= lambda x,y:x*2+y
print(r(5,2)) #12

def fib(n):if n==0 or n==1:return nelse:return fib(n-1)+fib(n-2)
print(fib(10))    # 55 

def hanoi(a,b,c,n):if n==1:print(a,'->',c)else:hanoi(a,c,b,n-1)print(a,'->',c)hanoi(b,a,c,n-1)
print(hanoi('a','b','c',3))

def fact(n):if n==0:return 1else:return n*fact(n-1)
print(fact(5)) #120

def reverse(s):if s=='':return selse:return s[-1]+reverse(s[0:-1]) # 或者reverse(s[1:])+s[0]
str='abcd'
print(reverse(str))  # dcba

def f(x):global a    print(a)a=5    print(a+x)
a=3
print(f(8)) # 13
print(a) # 5

from math import*
x=-2.3
print(ceil(x)) # -2
print(floor(x)) # -3
x=2.3
print(log(x))  # 以e为底 # 0.8329091229351039
print(sqrt(x)) # 1.51657508881031
print(exp(x)) # 9.974182454814718
print(log10(x)) # 0.36172783601759284
print(sin(x)) # 0.7457052121767203

os.getcwd()  # 获得当前工作目录
Out[33]: 'C:\\Users\\xuying_fall\\.spyder-py3'path='c:\\test'
os.chdir(path) # 修改当前目录
os.rename('test.txt','test1.txt') # 重命名
os.remove('test1.txt') # 删除文件

import random
random.randint(1,100)# 产生随机整数1-100之间
random.randrange(0,10,2) # 产生随机整数
random.random() # 随机浮点数, 包含0, 不包含1.0
random.uniform(5,10) # 产生5-10均匀分布随机浮点数,
random.sample(range(100),10)  # 获取10个元素作为样本 [23, 28, 39, 82, 2, 87, 25, 36, 32, 88]
a=[1,2,3,4]
random.shuffle(a)  # 将a 打乱顺序, 改变了a
print(a)  # [2, 4, 3, 1]

from random import*
seed(10)
print(random()) #  0.5714025946899135, [0,1]之间的小数
seed(10)
print(random()) #  0.5714025946899135 , #同一个seed下,产生的随机数是一样的

from random import *
from math import *
tol=3000 # 总次数
cnt=0 # 用于计数
for i in range(1,tol): # 实际tol取不到x,y=random(),random()  # 可以一起赋值d=sqrt(x**2+y**2)if d<=1.0:cnt+=1
pi=4*(cnt/tol)
print('pi is about %.2f'%pi)  # pi is about 3.18

from datetime import date
print(date.today())  # 2018-11-24from datetime import time
tm=time(23,20,15)
print(tm)  # 23:20:15from datetime import datetime
dt=datetime.now()
print(dt)  # 2018-11-24 13:21:48.968220# 格式转化, %a 本地简化的星期名称, %A本地完整的星期名称
print(dt.strftime('%a, %b %d %Y %H:%M ')) #
# Sat, Nov 24 2018 13 :43
print(dt.strftime('%A, %b %d %Y %H:%M '))
# Saturday, Nov 24 2018 13 :44
dt1=datetime(2018,6,6,23,29)
print(dt1) #  2018-06-06 23:29:00
ts=dt1.timestamp() # 把datetime转为全球统一的时间戳,
print(ts)# 1971-1-1,0时刻记作0, 当前时间为从该时刻开始的秒数,1528298940.0
print(datetime.fromtimestamp(ts)) # 把时间戳转为本地的时间,2018-06-06 23:29:00

try:num1=int(input('enter the first number:'))num2=int(input('enter the second number:'))print(num1/num2)
except ValueError: # ValueError异常类的名字print('please input a digit!')
# 没有异常就会忽略except 的语句
except ZeroDivisionError as err: #err存放错误原因print('the second number cannot be zero')print(err)# 多个except 语句捕捉多个异常, 也可以写在一起
try:num1=int(input('enter the first number:'))num2=int(input('enter the second number:'))print(num1/num2)
# 一个except 捕捉多个异常
except (ValueError,ZeroDivisionError)  #err存放错误原因print('invalid input!') 

try:num1=int(input('enter the first number:'))num2=int(input('enter the second number:'))print(num1/num2)
# 一个except 捕捉多个异常
except: print('something went wrong!')      

try:num1=int(input('enter the first number:'))num2=int(input('enter the second number:'))print(num1/num2)
# 一个except 捕捉多个异常
except Exception as err: #err存放错误原因print('something went wrong!')   print(err)
else:print('All right') 

while True:try:num1=int(input('enter the first number:'))num2=int(input('enter the second number:'))print(num1/num2)break# 一个except 捕捉多个异常except Exception as err: #err存放错误原因print('something went wrong!')   print(err)    else:print('All right')   

while True:try:num1=int(input('enter the first number:'))num2=int(input('enter the second number:'))print(num1/num2)break# 一个except 捕捉多个异常except Exception as err: #err存放错误原因print('something went wrong!')   print(err)    finally:print('this round is over')    

try: f=open('data.txt')for line in f:print(line,end=';')
except IOError:print('cannot open the file')
finally:f.close()

try: with open('data.txt') as f:for line in f:print(line,end=';')
except IOError:print('cannot open the file')

import math
def main():print('this programe is to find the real roots of equation\n')try:a,b,c=eval(input('please input three coefficients:'))dd=math.sqrt(b**2-4*a*c)r1=(-b+dd)/(2*a)r2=(-b-dd)/(2*a)print('the real roots are:',r1,r2)except :print('\n something went wrong, sorry')finally:print('\n maybe another try or quit')  # 无论是是否出错都会执行的语句
main()  # 调用函数

print('%c'%98) # b
print('%d+%d=%d'%(1,2,1+2))
print('%5.3f'%12.34) # 12.340 保留三位小数
s=1001.23
print('the total sum is %.2f'%s) # the total sum is 1001.23

result=1.09023
print('结果为：{}'.format(result))
print('{}'.format(result)) #结果为：1.09023
print('%.3f'%result) #浮点型保留三个小数,  1.090
print('%.0f'%result)  #不保留小数, 1
print('%d'%result)# 1

x=[1,3,5,2]
print (max(x)) # 5
print(sorted(x)) # [1, 2, 3, 5] , x没有改变
print(list(enumerate(x))) # [(0, 1), (1, 3), (2, 5), (3, 2)]

print (filter(None,[0,1,2,False,True]))  #[1, 2, True]选出true项
# 得到的只是<filter object at 0x0000021870326940>
# 加一个list就可以输出了
print (list(filter(None,[0,1,2,False,True])))  #[1, 2, True]选出true项print(list(filter(lambda x:x%2,range(10))))   #[1, 3, 5, 7, 9]选出奇数项,print(list(map(lambda x:x**2+1,range(4))))  # [1, 2, 5, 10] 集合映射逐一计算

a=['   ds','dd ']
b=[i.strip() for i in a]  #去空格, 精简的循环写法
print(b)   # ['ds', 'dd']
print (list(map(str.strip,a))) #两者等价 ['ds', 'dd'] , str表示库

vec=[(1,2),(3,4)]
c=[ j for i in vec for j in i]
print (c)  #每个元素取出来 [1, 2, 3, 4]print([(x,y)for x in range(2) for y in range(2)])
#得到[(0, 0), (0, 1), (1, 0), (1, 1)]