while补充，字符串和数字的内置方法

一、while循环的补充

while True:
    name=input('please input your name: ')
    password=input('please input your password: ')

    if name == 'egon' and password == '123':
        print('login successfull')
        while True:
            cmd=input('>>: ')
            if cmd == 'quit':
                break
            print('====>',cmd)
        break

tag=True
while tag:
    name=input('please input your name: ')
    password=input('please input your password: ')

    if name == 'egon' and password == '123':
        print('login successfull')
        while tag:
            cmd=input('>>: ')
            # if cmd == 'quit':
            #     tag=False
            #     continue
            # print('====>',cmd)

            if cmd == 'quit':
                tag=False
            else:
                print('====>',cmd)

while: else:的用法的

count=0
while count < 10:
    if count == 3:
        count+=1
        continue
    print(count)

    count+=1
else: #最后执行
    print('在最后执行，并且只有在while循环没有被break打断的情况下才执行')

二、字符串的内置方法

name='egon' #name=str('egon')
print(type(name))

优先掌握

移除空白strip

msg='             hello         '
print(msg)
print(msg.strip())

msg='***hello*********'
msg=msg.strip('*')
print(msg)

print(msg.lstrip('*'))
print(msg.rstrip('*'))

注：strip只能去除最左边以及最右边的空格，去除不了中间的空格

如：L= a a #三个空格夹着2个a

      print(L.strip())

输出的结果是a a

用处：我们不能控制用户的输入，为了判断方便，将无用部分剔除

例：剔除用户误输入的空格，以免影响判断

while True:
    name=input('user: ').strip()
    password=input('password: ').strip()

    if name == 'egon' and password == '123':
        print('login successfull')

切分split

字符串切分后变为列表，列表不能再进行切分

info='root:x:0:0::/root:/bin/bash'
print(info[0]+info[1]+info[2]+info[3])

user_l=info.split(':')
print(user_l[0])

msg='hello world egon say hahah'
print(msg.split()) #默认以空格作为分隔符

cmd='download|xhp.mov|3000'
cmd_l=cmd.split('|')
print(cmd_l[1])
print(cmd_l[0])

print(cmd.split('|',1))#后面的数字代表，切分次数，默认从左往右切分

用处：从字符串中切出用户命令的详细信息

while True:
    cmd=input('>>:　').strip()
    if len(cmd) == 0:continue
    cmd_l=cmd.split()
    print('命令是:%s 命令的参数是:%s' %(cmd_l[0],cmd_l[1]))

切片:切出子字符串

msg='hello world'
print(msg[1:3]) #1 2
print(msg[1:4]) #1 2 3

长度len

作用：算出字符串的长度（包括空格）
print(len('hell 123'))

索引

作用：找出字符串中某个字符在字符串中的位置
name='hell 123'
print(name.index('h'))


掌握部分

oldboy_age=84
while True:
    age=input('>>: ').strip()
    if len(age) == 0:continue
    if age.isdigit():
        age=int(age)
    else:
        print('must be int')





#startswith,endswith
name='alex_SB'
print(name.endswith('SB'))
print(name.startswith('alex'))


#replace
name='alex say :i have one tesla,my name is alex'
print(name.replace('alex','SB',1))

#format
print('my name is %s my age is %s my sex is %s' %('egon',18,'male'))
print('my name is {} my age is {} my sex is {}'.format('egon',18,'male'))
print('my name is {0} my age is {1} my sex is {0}:{2}'.format('egon',18,'male'))
print('my name is {name} my age is {age} my sex is {sex}'.format(
    sex='male',
    age=18,
    name='egon'))


name='goee say hello'
# print(name.find('S',1,3)) #顾头不顾尾,找不到则返回-1不会报错,找到了则显示索引
# print(name.index('S')) #同上,但是找不到会报错

print(name.count('S',1,5)) #顾头不顾尾,如果不指定范围则查找所有


#join
info='root:x:0:0::/root:/bin/bash'
print(info.split(':'))

l=['root', 'x', '0', '0', '', '/root', '/bin/bash']
print(':'.join(l))


#lower,upper
name='eGon'
print(name.lower())
print(name.upper())

了解部分

#expandtabs
name='egon	hello'
print(name)
print(name.expandtabs(1))


#center,ljust,rjust,zfill
name='egon'
# print(name.center(30,'-'))
print(name.ljust(30,'*'))
print(name.rjust(30,'*'))
print(name.zfill(50)) #用0填充


#captalize,swapcase,title
name='eGon'
print(name.capitalize()) #首字母大写,其余部分小写
print(name.swapcase()) #大小写翻转
msg='egon say hi'
print(msg.title()) #每个单词的首字母大写






#在python3中
num0='4'
num1=b'4' #bytes
num2=u'4' #unicode,python3中无需加u就是unicode
num3='四' #中文数字
num4='Ⅳ' #罗马数字


#isdigt:str,bytes,unicode
print(num0.isdigit())
print(num1.isdigit())
print(num2.isdigit())
print(num3.isdigit())
print(num4.isdigit())

#isdecimal:str,unicode
num0='4'
num1=b'4' #bytes
num2=u'4' #unicode,python3中无需加u就是unicode
num3='四' #中文数字
num4='Ⅳ' #罗马数字
print(num0.isdecimal())
# print(num1.)
print(num2.isdecimal())
print(num3.isdecimal())
print(num4.isdecimal())

#isnumeric:str,unicode,中文，罗马
num0='4'
num1=b'4' #bytes
num2=u'4' #unicode,python3中无需加u就是unicode
num3='四' #中文数字
num4='Ⅳ' #罗马数字

print(num0.isnumeric())
# print(num1)
print(num2.isnumeric())
print(num3.isnumeric())
print(num4.isnumeric())




#is其他
name='egon123'
print(name.isalnum()) #字符串由字母和数字组成
name='asdfasdfa sdf'
print(name.isalpha()) #字符串只由字母组成
#

name='asdfor123'
print(name.isidentifier())
name='egGon'
print(name.islower())
print(name.isupper())
print(name.isspace())
name='Egon say'
print(name.istitle())

判断用户输入的是否为整型数字，如果是，则转换成整型
oldboy_age=84
while True:
age=input('>>: ').strip()
if len(age) == 0:continue
if age.isdigit():
age=int(age)
else:
print('must be int')

字符串格式化方法
print('my name is {name} my age is {age} my sex is {sex}'.format(
sex='male',
age=18,
name='egon'))

三、数字的内置方法

=====>part1：数字类型
掌握：int，float
了解：Long（在python2中才有），complex

num=10
num=int(10)
print(type(num),num)

salary=12.5
salary=float(12.5)
print(type(salary),salary)




进制转换（了解部分）
二进制：0 1
1010101
res=1*(2**6)+1*(2**4)+1*(2**2)+1*1
print(res)

bin(11) #十进制的11转成二进制

八进制：0-7
print(oct(11))#十进制的11转成八进制


十六进制：0-9 a-f
print(hex(11))
print(hex(16))



复数
x=1-2j
print(x.real)
print(x.imag)