流程控制之判断
# 语法1# if 条件:# 代码1# 代码2# 代码3# ... # cls=‘human‘# sex=‘female‘# age=18## if cls == ‘human‘ and sex == ‘female‘ and age > 16 and age < 22:# print(‘开始表白‘)## print(‘end....‘)## # 语法2# if 条件:# 代码1# 代码2# 代码3# ...# else:# 代码1# 代码2# 代码3# ... # cls=‘human‘# sex=‘female‘# age=38## if cls == ‘human‘ and sex == ‘female‘ and age > 16 and age < 22:# print(‘开始表白‘)# else:# print(‘阿姨好‘)## print(‘end....‘) # 语法3# if 条件1:# 代码1# 代码2# 代码3# ...# elif 条件2:# 代码1# 代码2# 代码3# ...# elif 条件3:# 代码1# 代码2# 代码3# ...# ............# else:# 代码1# 代码2# 代码3# ... ‘‘‘如果：成绩>=90，那么：优秀 如果成绩>=80且<90,那么：良好 如果成绩>=70且<80,那么：普通 其他情况：很差 ‘‘‘ # score=input(‘your score: ‘) #score=‘73‘# score=int(score) #score=73# if score >= 90:# print(‘优秀‘)# elif score >= 80:# print(‘良好‘)# elif score >= 70:# print(‘普通‘)# else:# print(‘很差‘) # user_from_db=‘egon‘# pwd_from_db=‘123‘## user_from_inp=input(‘username>>>: ‘)# pwd_from_inp=input(‘password>>>: ‘)## if user_from_inp == user_from_db and pwd_from_inp == pwd_from_db:# print(‘login successfull‘)# else:# print(‘user or password error‘) #if的嵌套 cls=‘human‘sex=‘female‘age=18is_success=False if cls == ‘human‘ and sex == ‘female‘ and age > 16 and age < 22: print(‘开始表白...‘) if is_success: print(‘在一起‘) else: print(‘我逗你玩呢....‘)else: print(‘阿姨好‘) print(‘end....‘)
流程控制之while循环
#while语法,while循环又称为条件循环# while 条件:# code1# code2# code3# .... # user_db=‘egon‘# pwd_db=‘123‘## while True:# inp_user=input(‘username>>: ‘)# inp_pwd=input(‘password>>: ‘)# if inp_user == user_db and inp_pwd == pwd_db:# print(‘login successfull‘)# else:# print(‘user or password error‘) #2 while+break:break的意思是终止掉当前层的循环,.执行其他代码# while True:# print(‘1‘)# print(‘2‘)# break# print(‘3‘) # user_db=‘egon‘# pwd_db=‘123‘## while True:# inp_user=input(‘username>>: ‘)# inp_pwd=input(‘password>>: ‘)# if inp_user == user_db and inp_pwd == pwd_db:# print(‘login successfull‘)# break# else:# print(‘user or password error‘) # print(‘其他代码‘) #3 while+continue:continue的意思是终止掉本次循环,.直接进入下一次循环#ps:记住continue一定不要加到循环体最后一步执行的代码# n=1# while n <= 10: ## if n == 8:# n += 1 #n=9# continue# print(n)# n+=1 #n=11 # while True:# if 条件1:# code1# code2# code3# continue #无意义# elif 条件1:# code1# continue #有意义# code2# code3# elif 条件1:# code1# code2# code3# continue #无意义# ....# else:# code1# code2# code3# continue #无意义 #while循环嵌套user_db=‘egon‘pwd_db=‘123‘ while True: inp_user=input(‘username>>: ‘) inp_pwd=input(‘password>>: ‘) if inp_user == user_db and inp_pwd == pwd_db: print(‘login successfull‘) while True: cmd=input(‘请输入你要执行的命令: ‘) if cmd == ‘q‘: break print(‘%s 功能执行...‘ %cmd) break else: print(‘user or password error‘) print(‘end....‘) #while+taguser_db=‘egon‘pwd_db=‘123‘ tag=Truewhile tag: inp_user=input(‘username>>: ‘) inp_pwd=input(‘password>>: ‘) if inp_user == user_db and inp_pwd == pwd_db: print(‘login successfull‘) while tag: cmd=input(‘请输入你要执行的命令: ‘) if cmd == ‘q‘: tag=False else: print(‘%s 功能执行...‘ %cmd) else: print(‘user or password error‘) print(‘end....‘) #while+else (***)n=1while n < 5: # if n == 3: # break print(n) n+=1else: print(‘在整个循环结束后,会进行判断:只有while循环在没有被break结束掉的情况下才会执行else中的代码‘)
流程控制之for循环
# names=[‘egon‘,‘asb‘,‘wsb‘,‘lsb‘,‘csb‘]
# n=0# while n < len(names):# print(names[n])# n+=1
# names=[‘egon‘,‘asb‘,‘wsb‘,‘lsb‘,‘csb‘]# info={‘name‘:‘egon‘,‘age‘:18,‘sex‘:‘male‘}## # for k in info: #x=‘‘age‘# # print(k,info[k])## for item in names:# print(item)
# for i in range(1,10):# print(i)
# for i in range(10): #默认的起始位置是0# print(i)
# for i in range(1,10,2): #1 3 5 7 9# print(i)
# names=[‘egon‘,‘asb‘,‘wsb‘,‘lsb‘,‘csb‘]# for i in range(len(names)):# print(i,names[i])
# for i in range(5):# print(‘========>第一层: %s<=========‘ %i)# for j in range(3):# print(‘ 第二层: %s‘ %j)
#for+break# names=[‘asb‘,‘wsb‘,‘egon‘,‘lsb‘,‘csb‘]# for n in names:# if n == ‘egon‘:# break# print(n)
#for+continue# names=[‘asb‘,‘wsb‘,‘egon‘,‘lsb‘,‘csb‘]# for n in names:# if n == ‘egon‘:# continue# print(n)
#for+elsenames=[‘asb‘,‘wsb‘,‘egon‘,‘lsb‘,‘csb‘]for n in names: # if n == ‘egon‘: # break print(n)else: print(‘=====>‘)
原文地址：https://www.cnblogs.com/chillwave/p/9108540.html
时间： 2024-10-09 09:21:19