2018/09/04循环+运算
一:while循环
定义: 只要条件成立,就一直循环执行循环代码
机构:
while 条件:
循环执行代码
else:
执行代码2
例如:
while True:
print('0-0')
该函数则无限循环打印'0-0',直至天荒地老!
指令:break(推出本层循环)
continue(推出本次循环)
二格式化输出
占位符:% ( %d,占位指定取数值,%s: 占位指定取字符串,%r : 占位还原取值函数)
三 运算
python里面包含数学运算(如= - * / ),逻辑运算(and,or,not) 比较运算( == , <= ,<= 等)
and 并且。 左右两端同时为真。 结果才能是真
or 或者。 左右两端有一个是真。 结果就是真
not 非真即假， 非假即真
x or y -> ( 如果x为0,取y,否则取x)
x and y (如果x为0,则取X,否则取y)
运算顺序: () > not > and > or
编码:
最早的计算机编码:ASCII 占8位
中国:
GBK : 占16位
最早的万国码: unicode 占 32位
UTF-8: 可变长万国码,占位最短8位
UTF-16: 可变长万国码,占位最短16位
UTF-32: 可变长万国码,占位最短32位
print(1>1 or 3<4 or 4>5 and 2>1 and 9>8 or 7<6) #True
print(not 2 > 1 and 3 < 4 or 4 > 5 and 2 > 1 and 9 > 8 or 7 < 6 ) #false
print(8 or 3 and 4 or 2 and 0 or 9 and 7 ) #8
print(0 or 2 and 3 and 4 or 6 and 0 or 3 ) #4
print(6 or 2 > 1) #6
print(3 or 2 > 1) #3
print(0 or 5 < 4 ) # False
print(5<4 or 3) #3
print(2>1 or 6) # true
print(3 and 2>1) # 3
print(0 and 3>1) # 0
print(2>1 and 3) # 3
print(3>1 and 0) # 0
print(3>1 and 2 or 2<3 and 3 and 4 or 3>2) #2
while 条件:
执行代码1
else:
执行代码2
guess_num = int(input('请猜测幸运数字:'))
while guess_num != 66:
if guess_num > 66:
print('猜大了!')
guess_num = int(input('请猜测幸运数字:'))
elif guess_num < 66:
print('猜小了!')
guess_num = int(input('请猜测幸运数字:'))
else:
print('You are right !')
guess_num = int(input('请输入正确的数字:'))
count = 1
while guess_num != 66:
if count ==3:
print('Your are stupid !')
break
elif guess_num > 66:
print('猜大了!')
elif guess_num <66:
print('猜小了!')
elif guess_num == 66:
break
print('Your are right!')
count += 1
guess_num = int(input('请输入正确的数字:'))
else:
print('You are right !')
num = 1
while num <= 10:
if num != 7:
print(num)
num = num + 1
count = 1
while count <10:
count += 1
if count == 7:
continue
print(count)
sum = 0 count = 1
while count <= 100:
sum += count
count +=1
print(sum)
count = 1
while count <=50:
print(count * 2 -1)