day07--基本数据类型的常见使用方法

一、int类型与float类型

---

1、将纯数字类型转换成int

>>> res = int('1024')
>>> print(res,type(res))
1024 <class 'int'>

 2、进制之间的转换

十进制转换成二进制

14 -->  1 1 1 0
>>> print(bin(14))
0b1110
>>> 
>>> print(int('0b1110',2))
14
>>> 

 十进制转八进制

14 --> 16
>>> print(oct(14))
0o16
>>> 
>>> print(int('0o16',8))
14
>>> 

 十进制转十六进制

14 --> e
>>> print(hex(14))
0xe
>>> 

>>> print(int('0xe',16))
14
>>> 

进制运算主要用于数学运算和比较运算

二、字符串的内置方法

---

 1、字符串可以把其他任意类型的数据都转换成字符串

>>> msg = 'hello'
>>> print(msg,type(msg))
hello <class 'str'>
>>> 

>>> obj = str({'egon':19})
>>> print(obj,type(obj))
{'egon': 19} <class 'str'>
>>> 

>>> age = 19
>>> res = str(age)
>>> print(res,type(res))
19 <class 'str'>
>>> 

 2、字符串的内置方法

• 取值（正向取，反向取，对于字符串只能进行读操作）：

  正向取值
  >>> msg = 'hello world'
  >>> print(msg[0],msg[8])
  h r
  
  反向取值
  >>> print(msg[-1],msg[-3])
  d r
  >>> 

• 切片（从一个大字符串中拷贝出一个小字符串）

  正向取
  msg = 'hello world'
  >>> res = msg[0:5:1]
  >>> print(res,'
  ',msg)
  hello 
   hello world
  >>> 
  
  反向取
  >>> res = msg[5:0:-1]
  >>> print(res)
   olle
  >>> 
  
  >>> res = msg[-1::-1]
  >>> print(res)
  dlrow olleh
  >>> 

• 长度len

  >>> print(len(msg))
  11
  >>> 

• 成员运算in 和 not in

  >>> print('egon' in 'egon is very nb')
  True
  >>> 
  
  >>> print('tank' not in 'egon is very nb')
  True
  >>> 

• 移除字符串左右两侧的符号（默认为空格）

  >>> name = '  egon  '
  >>> print(name.strip(),name)
  egon   egon  
  >>> 
  
  >>> age_str = '****18***'
  >>> print(age_str.strip('*'),age_str)
  18 ****18***
  >>> 

• 切分split（默认分割符为空格）

  >>> str_obj = 'hellow egon, you are very nb'
  >>> print(str_obj.split(),'
  ',str_obj)
  ['hellow', 'egon,', 'you', 'are', 'very', 'nb'] 
   hellow egon, you are very nb
  >>> 
  
  指定字符分割
  >>> userfile_path = '/opt/nubosh/vmsec/upload'
  >>> print(userfile_path.split('/'),'
  ',userfile_path)
  ['', 'opt', 'nubosh', 'vmsec', 'upload'] 
   /opt/nubosh/vmsec/upload
  >>> 

• 需要掌握

  1、strip、lstrip、rstrip
  >>> name = ' egon '
  >>> print(name.strip())
  egon
  >>> print(name.lstrip())
  egon 
  >>> print(name.rstrip())
   egon
  
  2、lower、upper
  >>> obj = 'egon'
  >>> print(obj.upper())
  EGON
  >>> print(obj.lower())
  egon
  >>> 
  
  3、startswith、endswith
  >>> file_path = '/opt/nubosh/vmsec/vmsec.db'
  >>> print(file_path.endswith('db'))
  True
  >>> print(file_path.startswith('/'))
  True
  >>> 
  
  4、split、rsplit（指定分割次数）
  ['/opt/nubosh/vmsec', 'vmsec.db']
  >>> print(file_path.split('/',1))
  ['', 'opt/nubosh/vmsec/vmsec.db']
  >>> 
  
  5、format
  
  6、join字符串拼接
  file_path = '/opt/nubosh/vmsec/vmsec.db'
  >>> path_list = file_path.split('/')[0:-1:1]
  >>> print('/'.join(path_list+['log.txt']))
  /opt/nubosh/vmsec/log.txt
  >>> 
  
  7、replace
  >>> import time
  >>> current_time = time.ctime(time.time())
  >>> print(current_time)
  Tue Mar 10 16:57:26 2020
  >>> res = current_time.replace(':','/')
  >>> print(res)
  Tue Mar 10 16/57/26 2020
  >>> 
  
  8、判断字符串是否由纯数字组成
  >>> print('123'.isdigit())
  True
  >>> print('12.3'.isdigit())
  False
  >>> 

• 其他了解类型

  # 4.3了解
  
  #4.3.1、find,rfind,index,rindex,count
  
  msg='hello egon hahaha'
  
  # 找到返回起始索引
  
  # print(msg.find('e')) # 返回要查找的字符串在大字符串中的起始索引
  
  # print(msg.find('egon'))
  
  # print(msg.index('e'))
  
  # print(msg.index('egon'))
  
  # 找不到
  
  # print(msg.find('xxx')) # 返回-1，代表找不到
  
  # print(msg.index('xxx')) # 抛出异常
  
   
  
  # msg='hello egon hahaha egon、 egon'
  
  # print(msg.count('egon'))
  
   
  
  #4.3.2、center,ljust,rjust,zfill
  
  # print('egon'.center(50,'*'))
  
  # print('egon'.ljust(50,'*'))
  
  # print('egon'.rjust(50,'*'))
  
  # print('egon'.zfill(10))
  
   
  
  #4.3.3、expandtabs
  
  # msg='hello	world'
  
  # print(msg.expandtabs(2)) # 设置制表符代表的空格数为2
  
   
  
  #4.3.4、captalize,swapcase,title
  
  # print("hello world egon".capitalize())
  
  # print("Hello WorLd EGon".swapcase())
  
  # print("hello world egon".title())
  
   
  
  #4.3.5、is数字系列
  
  #4.3.6、is其他
  
  # print('abc'.islower())
  
  # print('ABC'.isupper())
  
  # print('Hello World'.istitle())
  
  # print('123123aadsf'.isalnum()) # 字符串由字母或数字组成结果为True
  
  # print('ad'.isalpha()) # 字符串由由字母组成结果为True
  
  # print('     '.isspace()) # 字符串由空格组成结果为True
  
  # print('print'.isidentifier())
  
  # print('age_of_egon'.isidentifier())
  
  # print('1age_of_egon'.isidentifier())
  
   
  
   
  
  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
  
   
  
  # isdigit只能识别：num1、num2
  
  # print(num1.isdigit()) # True
  
  # print(num2.isdigit()) # True
  
  # print(num3.isdigit()) # False
  
  # print(num4.isdigit()) # False
  
   
  
   
  
   
  
  # isnumberic可以识别：num2、num3、num4
  
  # print(num2.isnumeric()) # True
  
  # print(num3.isnumeric()) # True
  
  # print(num4.isnumeric()) # True
  
   
  
  # isdecimal只能识别：num2
  
  print(num2.isdecimal()) # True
  
  print(num3.isdecimal()) # False
  
  print(num4.isdecimal()) # False