python if while for 语句

python中的if语句与其他语言基本一致这里使用几个例子就能看懂

age_1 = 1
age_2 = 2
age_3 = 3
if age_1 < age_2 and (age_2 < age_3 or age_2 > age_3) : print('TRUE')
else : print('FLASE')
if age_1 > age_2 and age_2 < age_3 or age_2 > age_3 : print('TRUE')
else : print('FLASE')
#and优先级大于or 同时注意:不要忘记了

num = 5     
if num == 3:            # 判断num的值
    print ('boss')        
elif num == 2:
    print ('user')
elif num == 1:
    print ('worker')
elif num < 0:           # 值小于零时输出
    print ('error')
else:
    print ('roadman')     # 条件均不成立时输出

总结一下python与c在if的区别

1.and or 取代 && ||

2.and 优先级高于 or

3.字符串是一种基础数据类型可以直接 ==

检查特定值是否在列表中

array = [1,2,3,4,5]
print(1 in array)

同理not in

array = [1,2,3,4,5]
num = 6
if num not in array: 
    print('6 不在数字列表中')

同时我们知道了在python中布尔值使用 Ture 和 False

关于空列表

array = []
if array:
    print('I founded.')
else :
    print('are you kidding?')

while

在py中while循环与其它语言基本一致这里不再赘述

count = 1
while count <= 5:
    print(count)
    count += 1

使用while处理列表和字典

unconfirmed_user = ['jack','rose','tom']
user = []

while unconfirmed_user:#这里涉及到空列表的返回值是flase    
    current_user = unconfirmed_user.pop()
    print('verifying:'+str(current_user.title()))
    user.append(current_user)

print('condirmed user:')
for users in user:
    print(users)

删除特定的值

array = {1,2,3,4,5,1,2,1,2,3,1}
print (array)

while 1 in array:
    array.remove(1)
    
print(array)

demo:与用户交互投票调查统计结果

respone = {}

polling_active = True

while polling_active:
    name = input("\nwhat is your name?")
    respone_result = input("do you like me?")
    
    respone[name] = respone_result
    
    repeat = input('others want to join this?(y/n)')
    if repeat == 'n':
        polling_active = False
        
    print('-----------the poll result--------')
    for names,respones in respone.items():
        print(names,respones)

python if while for 语句

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