Python数据类型-数字类型、字符串

数字类型和字符串类型
1.bin()函数将十进制转换成而进制

2.oct()函数将十进制转换成八进制

3.hex()函数将十进制转换成十六进制

十六进制表示：0-9 a b c d e f

4.数字类型的特性：

只能存放一个值

一经定义，不可更改

直接访问

分类：整型，布尔，浮点，复数

5.字符串类型

引号包含的都是字符串类型

S1=‘hello world’ s=“hello world”

s2=“”“hello world”“”

s3=‘’‘hello world’‘’

单引双引没有区别

6.字符串的常用操作

strip()移除空白，也可以去除其他的字符

slipt()分割,默认以空格分割。也可以以其他的字符分割

len()长度 切片：如print(x[1:3])也是顾头不顾尾

print(x[0:5:2])#0 2 4

capitalize()首字母大写

center()居中显示例如：x=‘hello’ print(x.center(30,‘#’))

count():计数，顾头不顾尾，统计某个字符的个数，空格也算一个字符

endswith()以什么结尾

satrtswith()以什么开头

find()查找字符的索引位置，如果是负数，代表查找失败

index()索引

find()和index()的区别，如下图：

format()字符串格式化

1.msg=‘name:{},age:{},sex:{}’

print(msg.format(‘haiyan’,18,女))

2.msg=‘name:{0},age:{1},sex:{0}’

print(msg.format(‘aaaaaa’,‘bbbbbb’))

3.msg=‘name:{x},age:{y,sex:{z}’

print(msg.format(x=‘haiyan’,y=‘18’,z=‘女’))

isdigit()判断是否是数字

islower()判断是否是全部小写

isupper()判断是否是全部大写

lower()全部转换为小写

upper()全部转换为大写

isspace()判断是否是全都是空格

istitle()判断是否是标题（首字母大写）

swapcase()大小写字母翻转

join()连接

repalce()替换

msg=‘hello alex’

print(msg.replace(‘e’),‘A’,1)

print(msg.replace(‘e’),‘A’,2)

ljust()左对齐

X=‘ABC’ print(x.ljust(10,‘*’))

字符串格式化及字符串的一些方法
1.%s,%d

举例1：name=‘egon’

age=20

print(“my name is %s my age is %s” %(name,age))#%s既能接受字符串，也能接受数字

print(‘my name is %s my age is %d’ %(name,age))#%d只能接受数字

举例2：用户信息的显示

复制代码
1 while True:
2 name=input(“name:”)
3 age=input(“age:”)
4 sex=input(“sex:”)
5 height=input(“height:”)
6 msg=‘’’
7 ------------%s info-----------
8 name:%s
9 age:%s
10 sex:%s
11 height:%s
12 ------------------------------
13 ‘’'%(name,name,age,sex,heigth)
14 print(msg)
复制代码
运行结果如下：

while True:
    name=input("name:")
    age=input("age:")
    sex=input("sex:")
    height=input("height:")
    msg='''
             ------------%s info-----------
             name:%s
             age:%s
             sex:%s
             height:%s
             ------------------------------
        '''%(name,name,age,sex,heigth)
    print(msg)

2.字符串方法

name=‘egon’ #name=str(‘egon’)

print(type(name))

#优先掌握
#1.移除空白strip

msg=’ hello ’

print(msg)

print(msg.strip())

移除‘*’

msg=‘hello******’

msg=msg.strip(‘*’)

print(msg)

#移除左边的

print(msg.lstrip(‘*’))

#移除右边的

print(msg.rstrip(‘*’))

#用处
while True:
name=input('user: ').strip()
password=input('password: ').strip()
if name == ‘egon’ and password == ‘123’:
print(‘login successfull’)

#切分split

info=‘root❌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))

#用处
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]))

#长度len

print(len(‘hell 123’))

#索引

切片:切出子字符串

msg=‘hello world’

print(msg[1:3]) #1 2

print(msg[1:4]) #1 2 3

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))

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❌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\thello’

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())