第二天知识总结

print(6 or 2 > 1)
print(0 or 5 < 4)
print(5 < 4 or 3)
print(3 and 2 > 1)
print(0 and 3 > 1)
print(2 > 1 and 3)
print(3 > 1 and 0) # 要满足两边都是真才是真，所有此时输出0而不是f

count = 1
sum = 0
while count < 100:
    if count == 88:
        count += 1
        continue
    elif count % 2 == 0:
        sum = sum - count
    else:
        sum = sum + count
    count += 1
print(sum)

count = 0
i = -1
sum = 0
while count < 99:
    count += 1
    if count == 88:
        continue
    else:
        i = -i
        sum = sum + count * i
print(sum)

i = 3
username = ‘小明‘
password = ‘123456‘
while i > 0:
    name = input(‘请输入用户名‘)
    i -= 1
    if username == name:
        pwd = input(‘请输入密码‘)
        if pwd == password:
            print(‘登录成功，请稍后...‘)
            print(‘‘‘恭喜登录成功！
            欢迎%s的进入
            ‘‘‘%(name))
            break
        else:
            if i == 0:
                print(‘输入错误，你的机会已经用完‘)
                break
            print(‘密码错误，请重新输入‘)
            print(‘你还有‘+str(i)+‘次机会‘)
    else:
        if i == 0:
            print(‘输入错误，你的机会已经用完‘)
            break
        print(‘请输入正确的用户名‘)
        print(‘你还有‘ + str(i) + ‘次机会‘)
        if i == 0:
            print(‘输入错误，你的机会已经用完‘)
            print(‘你还有‘+str(i)+‘次机会‘)

s = ‘jackDSs‘
a = s.capitalize()  # 首字母大写
print(a)
b = s.upper()  # 全大写
print(b)
c = s.lower()  # 全小写
print(c)
d = s.swapcase()  # 大小写翻转
print(d)
# 例子(验证码的写法)
s_str = ‘ahRT123‘
you_input = input(‘请输入验证码‘)
if s_str.upper() == you_input.upper():  # 也可以全变小写
    print(‘输入正确‘)
else:
    print(‘输入错误，请重新输入‘)
#
s1 = ‘some*table-student$char5count jack‘
e = s1.title()  # 每个隔开（特殊字符或者数字）的单词首字母大写
print(e)
#
f = s.center(20,‘&‘)  # 居中，center（宽度，填充字符可以为空）
print(f)
#
s2 = ‘name五十二‘
g = len(s2)  # 计算多少字符
print(g)
#
s3 = ‘sametable‘
h = s3.startswith(‘sa‘,3,5)  # 判断是以什么开头结尾，startswith(以什么开头，左开右闭的区间‘可以不写’)
h1 = s3.endswith(‘e‘)  # 以什么为结尾
print(h,h1)
#
s4 = ‘sfsnTUR‘
g = s4.find(‘T‘)  # 通过元素找索引，找不到返回-1（index功能一样，但是找不到就报错）
print(g)
#
s5 = ‘   sdfst   ‘
s5_1 = ‘%sfsf*‘
h = s5.strip()  # 默认删除前后空格,strip(‘字符‘),中间的不能删除,rstrip()和lstri分别是只删左边和只删右边的意思
h1 = s5_1.strip(‘%*‘)
print(h,h1)
# 例子(在用户输入的时候)
username = input(‘请输入用户名‘).strip()
if username == ‘小明‘:
    print(‘输入正确‘)
else:print(‘输入错误‘)
#
s6 = ‘sfsg sfasf‘
i = s6.count(‘s‘)  # 统计个数,可切片统计
print(i)
#
s7 = ‘sfasf%saf%afa‘
j = s7.split(‘%‘)  # 分割，相当于把str转换为list(列表);split(默认为空隔)
print(j)

s8 = ‘我叫{},今年{},爱好{},再说一声我叫{}‘.format(‘小明‘,‘20‘,‘游戏‘,‘小明‘)
print(s8)
s8 = ‘我叫{0},今年{1},爱好{2},再说一声我叫{0}‘.format(‘小明‘,‘20‘,‘游戏‘)
print(s8)
s8 = ‘我叫{name},今年{age},爱好{hobby},再说一声我叫{name}‘.format(age=‘20‘,name=‘小明‘,hobby=‘游戏‘)
print(s8)

s9 = ‘明天真好啊明天‘
k = s9.replace(‘明天‘,‘今天‘)  # 默认全部替换
k2 = s9.replace(‘明天‘,‘今天‘,1)  # 只替换规定的
print(k,k2)

s10 = ‘xiaoming123‘
m = s10.isalnum()  # 字符串由字母和数字组成
print(m)
m1 = s10.isalpha()  # 字符串只由字母组成
print(m1)
m2 = s10.isdigit()  # 字符串只由数字组成
print(m2)

s11 = ‘akljsfkl‘
for n in s11:
    print(n)
s11_1 = ‘明天杀了他‘
if ‘杀‘ in s11_1:  # 也有(not in)
    print(‘你输入有敏感字‘)