常量：
python中没有常量，只能通过名字特征来提示
例如：
全部大写，如： OLDBOY_AGE=57

变量
声明变量
#!/usr/bin/env python

age=18
gender1='male' 
gender2='female'

变量作用：保存状态（程序的运行本质是一系列状态的变化，变量的目的就是用来保存状态，变量值的变化就构成了程序运行的不同结果。）
例如：CS枪战，一个人的生命可以表示为life＝active表示存活，当满足某种条件后修改变量life＝inactive表示死亡。

变量命名规则遵循标识符命名规则，详见第二篇
name＝'lhf':'lhf'才是内存变量，name只是内存变量的引用
与c的区别在于变量赋值操作无返回值
链式赋值：y＝x＝a＝1
多元赋值：x,y=1,2 x,y=y,x
增量赋值：x+=1

二.数据类型

2.1 什么是数据类型及数据类型分类

程序的本质就是驱使计算机去处理各种状态的变化，这些状态分为很多种

例如英雄联盟游戏，一个人物角色有名字，钱，等级，装备等特性，大家第一时间会想到这么表示
名字：德玛西亚－－－－－－－－－－－－>字符串
钱：10000   －－－－－－－－－－－－>数字
等级：15    －－－－－－－－－－－－>数字
装备：鞋子，日炎斗篷，兰顿之兆－－－－>列表
(记录这些人物特性的是变量，这些特性的真实存在则是变量的值，存不同的特性需要用不同类型的值)

python中的数据类型
python使用对象模型来存储数据，每一个数据类型都有一个内置的类，每新建一个数据，实际就是在初始化生成一个对象，即所有数据都是对象
对象三个特性

身份：内存地址，可以用id()获取
类型：决定了该对象可以保存什么类型值，可执行何种操作，需遵循什么规则，可用type()获取
值：对象保存的真实数据

注：我们在定义数据类型，只需这样：x＝1，内部生成1这一内存对象会自动触发，我们无需关心


这里的字符串、数字、列表等都是数据类型（用来描述某种状态或者特性）除此之外还有很多其他数据，处理不同的数据就需要定义不同的数据类型

标准类型	其他类型
数字	类型type
字符串	Null
列表	文件
元组	集合
字典	函数／方法
	类
	模块

2.2 标准数据类型：

2.2.1 数字

定义：a＝1

特性：

1.只能存放一个值

2.一经定义，不可更改

3.直接访问

分类：整型，长整型，布尔，浮点，复数

2.2.1.1 整型:

Python的整型相当于C中的long型,Python中的整数可以用十进制,八进制,十六进制表示。

>>> 10
10         --------->默认十进制
>>> oct(10)
'012'      --------->八进制表示整数时，数值前面要加上一个前缀“0”
>>> hex(10)
'0xa'      --------->十六进制表示整数时，数字前面要加上前缀0X或0x

python2.*与python3.*关于整型的区别

python2.*
在32位机器上，整数的位数为32位，取值范围为-2**31～2**31-1，即-2147483648～2147483647

在64位系统上，整数的位数为64位，取值范围为-2**63～2**63-1，即-9223372036854775808～9223372036854775807
python3.*整形长度无限制

2.2.1.2 长整型long：

python2.*：
跟C语言不同，Python的长整型没有指定位宽，也就是说Python没有限制长整型数值的大小，
但是实际上由于机器内存有限，所以我们使用的长整型数值不可能无限大。
在使用过程中，我们如何区分长整型和整型数值呢？
通常的做法是在数字尾部加上一个大写字母L或小写字母l以表示该整数是长整型的，例如：
a = 9223372036854775808L
注意，自从Python2起，如果发生溢出，Python会自动将整型数据转换为长整型，
所以如今在长整型数据后面不加字母L也不会导致严重后果了。

python3.*
长整型，整型统一归为整型

python2.7
>>> a=9223372036854775807
>>> a
>>> a+=1
>>> a
9223372036854775808L

python3.5
>>> a=9223372036854775807
>>> a
>>> a+=1
>>> a

查看

'''
# print(type(n))
# print(type(f))

# print(1.3e-3)
# print(1.3e3)



# print(bin(10))     #二进制
# print(oct(10))     #八进制
# # 0-9 a b c d e f
# print(hex(10))     #16进制
'''


#数字类型的特点：
# 1.只能存放一个值
#
# 2.一经定义，不可更改，更改的是变量和值的对应关系
#
# 3.直接访问
# x=10123123123
# print(id(x))
# x=11
# print(id(x))
# print(id(11))
#====================运行结果：=====================
# D:Python36python.exe D:/py/train.py
# 2368243792624
# 1640347008
# 1640347008
# Process finished with exit code 0
#================================================

2.2.1.3 布尔bool:

True 和False
1和0

2.2.1.4 浮点数float:

Python的浮点数就是数学中的小数，类似C语言中的double。
在运算中，整数与浮点数运算的结果是浮点数
浮点数也就是小数，之所以称为浮点数，是因为按照科学记数法表示时，
一个浮点数的小数点位置是可变的，比如，1.23*109和12.3*108是相等的。
浮点数可以用数学写法，如1.23，3.14，-9.01，等等。但是对于很大或很小的浮点数，
就必须用科学计数法表示，把10用e替代，1.23*109就是1.23e9，或者12.3e8，0.000012
可以写成1.2e-5，等等。
整数和浮点数在计算机内部存储的方式是不同的，整数运算永远是精确的而浮点数运算则可能会有
四舍五入的误差。

2.2.1.5 复数complex:

复数由实数部分和虚数部分组成，一般形式为x＋yj，其中的x是复数的实数部分，y是复数的虚数部分，这里的x和y都是实数。
注意，虚数部分的字母j大小写都可以，

>>> 1.3 + 2.5j == 1.3 + 2.5J
True

2.2.1.6 数字相关内建函数

Python（变量、数据类型）
一.变量
二.数据类型
三算数运算；逻辑运算；比较运算；关系运算；
四.标准数据类型特性总结

2.2.2 字符串

定义：它是一个有序的字符的集合，用于存储和表示基本的文本信息，‘’或“”或‘’‘ ’‘’中间包含的内容称之为字符串
特性：
1.只能存放一个值
2.不可变
3.按照从左到右的顺序定义字符集合，下标从0开始顺序访问，有序
补充：
　　1.字符串的单引号和双引号都无法取消特殊字符的含义，如果想让引号内所有字符均取消特殊意义，在引号前面加r，如name＝r'l	hf'
　　2.unicode字符串与r连用必需在r前面，如name＝ur'l	hf'

2.2.2.1 字符串创建

‘hello world’

2.2.2.2 字符串常用操作

移除空白
分割
长度
索引
切片

2.2.2.3 字符工厂函数str()

  1 class str(object):
  2     """
  3     str(object='') -> str
  4     str(bytes_or_buffer[, encoding[, errors]]) -> str
  5 
  6     Create a new string object from the given object. If encoding or
  7     errors is specified, then the object must expose a data buffer
  8     that will be decoded using the given encoding and error handler.
  9     Otherwise, returns the result of object.__str__() (if defined)
 10     or repr(object).
 11     encoding defaults to sys.getdefaultencoding().
 12     errors defaults to 'strict'.
 13     """
 14     def capitalize(self): # real signature unknown; restored from __doc__
 15         """
 16         首字母变大写
 17         S.capitalize() -> str
 18 
 19         Return a capitalized version of S, i.e. make the first character
 20         have upper case and the rest lower case.
 21         """
 22         return ""
 23 
 24     def casefold(self): # real signature unknown; restored from __doc__
 25         """
 26         S.casefold() -> str
 27 
 28         Return a version of S suitable for caseless comparisons.
 29         """
 30         return ""
 31 
 32     def center(self, width, fillchar=None): # real signature unknown; restored from __doc__
 33         """
 34         原来字符居中，不够用空格补全
 35         S.center(width[, fillchar]) -> str
 36 
 37         Return S centered in a string of length width. Padding is
 38         done using the specified fill character (default is a space)
 39         """
 40         return ""
 41 
 42     def count(self, sub, start=None, end=None): # real signature unknown; restored from __doc__
 43         """
 44          从一个范围内的统计某str出现次数
 45         S.count(sub[, start[, end]]) -> int
 46 
 47         Return the number of non-overlapping occurrences of substring sub in
 48         string S[start:end].  Optional arguments start and end are
 49         interpreted as in slice notation.
 50         """
 51         return 0
 52 
 53     def encode(self, encoding='utf-8', errors='strict'): # real signature unknown; restored from __doc__
 54         """
 55         encode(encoding='utf-8',errors='strict')
 56         以encoding指定编码格式编码，如果出错默认报一个ValueError，除非errors指定的是
 57         ignore或replace
 58 
 59         S.encode(encoding='utf-8', errors='strict') -> bytes
 60 
 61         Encode S using the codec registered for encoding. Default encoding
 62         is 'utf-8'. errors may be given to set a different error
 63         handling scheme. Default is 'strict' meaning that encoding errors raise
 64         a UnicodeEncodeError. Other possible values are 'ignore', 'replace' and
 65         'xmlcharrefreplace' as well as any other name registered with
 66         codecs.register_error that can handle UnicodeEncodeErrors.
 67         """
 68         return b""
 69 
 70     def endswith(self, suffix, start=None, end=None): # real signature unknown; restored from __doc__
 71         """
 72         S.endswith(suffix[, start[, end]]) -> bool
 73 
 74         Return True if S ends with the specified suffix, False otherwise.
 75         With optional start, test S beginning at that position.
 76         With optional end, stop comparing S at that position.
 77         suffix can also be a tuple of strings to try.
 78         """
 79         return False
 80 
 81     def expandtabs(self, tabsize=8): # real signature unknown; restored from __doc__
 82         """
 83         将字符串中包含的	转换成tabsize个空格
 84         S.expandtabs(tabsize=8) -> str
 85 
 86         Return a copy of S where all tab characters are expanded using spaces.
 87         If tabsize is not given, a tab size of 8 characters is assumed.
 88         """
 89         return ""
 90 
 91     def find(self, sub, start=None, end=None): # real signature unknown; restored from __doc__
 92         """
 93         S.find(sub[, start[, end]]) -> int
 94 
 95         Return the lowest index in S where substring sub is found,
 96         such that sub is contained within S[start:end].  Optional
 97         arguments start and end are interpreted as in slice notation.
 98 
 99         Return -1 on failure.
100         """
101         return 0
102 
103     def format(self, *args, **kwargs): # known special case of str.format
104         """
105         格式化输出
106         三种形式：
107         形式一.
108         >>> print('{0}{1}{0}'.format('a','b'))
109         aba
110 
111         形式二：（必须一一对应）
112         >>> print('{}{}{}'.format('a','b'))
113         Traceback (most recent call last):
114           File "<input>", line 1, in <module>
115         IndexError: tuple index out of range
116         >>> print('{}{}'.format('a','b'))
117         ab
118 
119         形式三：
120         >>> print('{name} {age}'.format(age=12,name='lhf'))
121         lhf 12
122 
123         S.format(*args, **kwargs) -> str
124 
125         Return a formatted version of S, using substitutions from args and kwargs.
126         The substitutions are identified by braces ('{' and '}').
127         """
128         pass
129 
130     def format_map(self, mapping): # real signature unknown; restored from __doc__
131         """
132         与format区别
133         '{name}'.format(**dict(name='alex'))
134         '{name}'.format_map(dict(name='alex'))
135 
136         S.format_map(mapping) -> str
137 
138         Return a formatted version of S, using substitutions from mapping.
139         The substitutions are identified by braces ('{' and '}').
140         """
141         return ""
142 
143     def index(self, sub, start=None, end=None): # real signature unknown; restored from __doc__
144         """
145         S.index(sub[, start[, end]]) -> int
146 
147         Like S.find() but raise ValueError when the substring is not found.
148         """
149         return 0
150 
151     def isalnum(self): # real signature unknown; restored from __doc__
152         """
153         至少一个字符，且都是字母或数字才返回True
154 
155         S.isalnum() -> bool
156 
157         Return True if all characters in S are alphanumeric
158         and there is at least one character in S, False otherwise.
159         """
160         return False
161 
162     def isalpha(self): # real signature unknown; restored from __doc__
163         """
164         至少一个字符，且都是字母才返回True
165         S.isalpha() -> bool
166 
167         Return True if all characters in S are alphabetic
168         and there is at least one character in S, False otherwise.
169         """
170         return False
171 
172     def isdecimal(self): # real signature unknown; restored from __doc__
173         """
174         S.isdecimal() -> bool
175 
176         Return True if there are only decimal characters in S,
177         False otherwise.
178         """
179         return False
180 
181     def isdigit(self): # real signature unknown; restored from __doc__
182         """
183         S.isdigit() -> bool
184 
185         Return True if all characters in S are digits
186         and there is at least one character in S, False otherwise.
187         """
188         return False
189 
190     def isidentifier(self): # real signature unknown; restored from __doc__
191         """
192         字符串为关键字返回True
193 
194         S.isidentifier() -> bool
195 
196         Return True if S is a valid identifier according
197         to the language definition.
198 
199         Use keyword.iskeyword() to test for reserved identifiers
200         such as "def" and "class".
201         """
202         return False
203 
204     def islower(self): # real signature unknown; restored from __doc__
205         """
206         至少一个字符，且都是小写字母才返回True
207         S.islower() -> bool
208 
209         Return True if all cased characters in S are lowercase and there is
210         at least one cased character in S, False otherwise.
211         """
212         return False
213 
214     def isnumeric(self): # real signature unknown; restored from __doc__
215         """
216         S.isnumeric() -> bool
217 
218         Return True if there are only numeric characters in S,
219         False otherwise.
220         """
221         return False
222 
223     def isprintable(self): # real signature unknown; restored from __doc__
224         """
225         S.isprintable() -> bool
226 
227         Return True if all characters in S are considered
228         printable in repr() or S is empty, False otherwise.
229         """
230         return False
231 
232     def isspace(self): # real signature unknown; restored from __doc__
233         """
234         至少一个字符，且都是空格才返回True
235         S.isspace() -> bool
236 
237         Return True if all characters in S are whitespace
238         and there is at least one character in S, False otherwise.
239         """
240         return False
241 
242     def istitle(self): # real signature unknown; restored from __doc__
243         """
244         >>> a='Hello'
245         >>> a.istitle()
246         True
247         >>> a='HellP'
248         >>> a.istitle()
249         False
250 
251         S.istitle() -> bool
252 
253         Return True if S is a titlecased string and there is at least one
254         character in S, i.e. upper- and titlecase characters may only
255         follow uncased characters and lowercase characters only cased ones.
256         Return False otherwise.
257         """
258         return False
259 
260     def isupper(self): # real signature unknown; restored from __doc__
261         """
262         S.isupper() -> bool
263 
264         Return True if all cased characters in S are uppercase and there is
265         at least one cased character in S, False otherwise.
266         """
267         return False
268 
269     def join(self, iterable): # real signature unknown; restored from __doc__
270         """
271         #对序列进行操作（分别使用' '与':'作为分隔符）
272         >>> seq1 = ['hello','good','boy','doiido']
273         >>> print ' '.join(seq1)
274         hello good boy doiido
275         >>> print ':'.join(seq1)
276         hello:good:boy:doiido
277 
278 
279         #对字符串进行操作
280 
281         >>> seq2 = "hello good boy doiido"
282         >>> print ':'.join(seq2)
283         h:e:l:l:o: :g:o:o:d: :b:o:y: :d:o:i:i:d:o
284 
285 
286         #对元组进行操作
287 
288         >>> seq3 = ('hello','good','boy','doiido')
289         >>> print ':'.join(seq3)
290         hello:good:boy:doiido
291 
292 
293         #对字典进行操作
294 
295         >>> seq4 = {'hello':1,'good':2,'boy':3,'doiido':4}
296         >>> print ':'.join(seq4)
297         boy:good:doiido:hello
298 
299 
300         #合并目录
301 
302         >>> import os
303         >>> os.path.join('/hello/','good/boy/','doiido')
304         '/hello/good/boy/doiido'
305 
306 
307         S.join(iterable) -> str
308 
309         Return a string which is the concatenation of the strings in the
310         iterable.  The separator between elements is S.
311         """
312         return ""
313 
314     def ljust(self, width, fillchar=None): # real signature unknown; restored from __doc__
315         """
316         S.ljust(width[, fillchar]) -> str
317 
318         Return S left-justified in a Unicode string of length width. Padding is
319         done using the specified fill character (default is a space).
320         """
321         return ""
322 
323     def lower(self): # real signature unknown; restored from __doc__
324         """
325         S.lower() -> str
326 
327         Return a copy of the string S converted to lowercase.
328         """
329         return ""
330 
331     def lstrip(self, chars=None): # real signature unknown; restored from __doc__
332         """
333         S.lstrip([chars]) -> str
334 
335         Return a copy of the string S with leading whitespace removed.
336         If chars is given and not None, remove characters in chars instead.
337         """
338         return ""
339 
340     def maketrans(self, *args, **kwargs): # real signature unknown
341         """
342         Return a translation table usable for str.translate().
343 
344         If there is only one argument, it must be a dictionary mapping Unicode
345         ordinals (integers) or characters to Unicode ordinals, strings or None.
346         Character keys will be then converted to ordinals.
347         If there are two arguments, they must be strings of equal length, and
348         in the resulting dictionary, each character in x will be mapped to the
349         character at the same position in y. If there is a third argument, it
350         must be a string, whose characters will be mapped to None in the result.
351         """
352         pass
353 
354     def partition(self, sep): # real signature unknown; restored from __doc__
355         """
356         以sep为分割，将S分成head,sep,tail三部分
357 
358         S.partition(sep) -> (head, sep, tail)
359 
360         Search for the separator sep in S, and return the part before it,
361         the separator itself, and the part after it.  If the separator is not
362         found, return S and two empty strings.
363         """
364         pass
365 
366     def replace(self, old, new, count=None): # real signature unknown; restored from __doc__
367         """
368         S.replace(old, new[, count]) -> str
369 
370         Return a copy of S with all occurrences of substring
371         old replaced by new.  If the optional argument count is
372         given, only the first count occurrences are replaced.
373         """
374         return ""
375 
376     def rfind(self, sub, start=None, end=None): # real signature unknown; restored from __doc__
377         """
378         S.rfind(sub[, start[, end]]) -> int
379 
380         Return the highest index in S where substring sub is found,
381         such that sub is contained within S[start:end].  Optional
382         arguments start and end are interpreted as in slice notation.
383 
384         Return -1 on failure.
385         """
386         return 0
387 
388     def rindex(self, sub, start=None, end=None): # real signature unknown; restored from __doc__
389         """
390         S.rindex(sub[, start[, end]]) -> int
391 
392         Like S.rfind() but raise ValueError when the substring is not found.
393         """
394         return 0
395 
396     def rjust(self, width, fillchar=None): # real signature unknown; restored from __doc__
397         """
398         S.rjust(width[, fillchar]) -> str
399 
400         Return S right-justified in a string of length width. Padding is
401         done using the specified fill character (default is a space).
402         """
403         return ""
404 
405     def rpartition(self, sep): # real signature unknown; restored from __doc__
406         """
407         S.rpartition(sep) -> (head, sep, tail)
408 
409         Search for the separator sep in S, starting at the end of S, and return
410         the part before it, the separator itself, and the part after it.  If the
411         separator is not found, return two empty strings and S.
412         """
413         pass
414 
415     def rsplit(self, sep=None, maxsplit=-1): # real signature unknown; restored from __doc__
416         """
417         S.rsplit(sep=None, maxsplit=-1) -> list of strings
418 
419         Return a list of the words in S, using sep as the
420         delimiter string, starting at the end of the string and
421         working to the front.  If maxsplit is given, at most maxsplit
422         splits are done. If sep is not specified, any whitespace string
423         is a separator.
424         """
425         return []
426 
427     def rstrip(self, chars=None): # real signature unknown; restored from __doc__
428         """
429         S.rstrip([chars]) -> str
430 
431         Return a copy of the string S with trailing whitespace removed.
432         If chars is given and not None, remove characters in chars instead.
433         """
434         return ""
435 
436     def split(self, sep=None, maxsplit=-1): # real signature unknown; restored from __doc__
437         """
438         以sep为分割，将S切分成列表，与partition的区别在于切分结果不包含sep，
439         如果一个字符串中包含多个sep那么maxsplit为最多切分成几部分
440         >>> a='a,b c
d	e'
441         >>> a.split()
442         ['a,b', 'c', 'd', 'e']
443         S.split(sep=None, maxsplit=-1) -> list of strings
444 
445         Return a list of the words in S, using sep as the
446         delimiter string.  If maxsplit is given, at most maxsplit
447         splits are done. If sep is not specified or is None, any
448         whitespace string is a separator and empty strings are
449         removed from the result.
450         """
451         return []
452 
453     def splitlines(self, keepends=None): # real signature unknown; restored from __doc__
454         """
455         Python splitlines() 按照行('
', '
', 
')分隔，
456         返回一个包含各行作为元素的列表，如果参数 keepends 为 False，不包含换行符，如        果为 True，则保留换行符。
457         >>> x
458         'adsfasdf
sadf
asdf
adf'
459         >>> x.splitlines()
460         ['adsfasdf', 'sadf', 'asdf', 'adf']
461         >>> x.splitlines(True)
462         ['adsfasdf
', 'sadf
', 'asdf
', 'adf']
463 
464         S.splitlines([keepends]) -> list of strings
465 
466         Return a list of the lines in S, breaking at line boundaries.
467         Line breaks are not included in the resulting list unless keepends
468         is given and true.
469         """
470         return []
471 
472     def startswith(self, prefix, start=None, end=None): # real signature unknown; restored from __doc__
473         """
474         S.startswith(prefix[, start[, end]]) -> bool
475 
476         Return True if S starts with the specified prefix, False otherwise.
477         With optional start, test S beginning at that position.
478         With optional end, stop comparing S at that position.
479         prefix can also be a tuple of strings to try.
480         """
481         return False
482 
483     def strip(self, chars=None): # real signature unknown; restored from __doc__
484         """
485         S.strip([chars]) -> str
486 
487         Return a copy of the string S with leading and trailing
488         whitespace removed.
489         If chars is given and not None, remove characters in chars instead.
490         """
491         return ""
492 
493     def swapcase(self): # real signature unknown; restored from __doc__
494         """
495         大小写反转
496         S.swapcase() -> str
497 
498         Return a copy of S with uppercase characters converted to lowercase
499         and vice versa.
500         """
501         return ""
502 
503     def title(self): # real signature unknown; restored from __doc__
504         """
505         S.title() -> str
506 
507         Return a titlecased version of S, i.e. words start with title case
508         characters, all remaining cased characters have lower case.
509         """
510         return ""
511 
512     def translate(self, table): # real signature unknown; restored from __doc__
513         """
514         table=str.maketrans('alex','big SB')
515 
516         a='hello abc'
517         print(a.translate(table))
518 
519         S.translate(table) -> str
520 
521         Return a copy of the string S in which each character has been mapped
522         through the given translation table. The table must implement
523         lookup/indexing via __getitem__, for instance a dictionary or list,
524         mapping Unicode ordinals to Unicode ordinals, strings, or None. If
525         this operation raises LookupError, the character is left untouched.
526         Characters mapped to None are deleted.
527         """
528         return ""
529 
530     def upper(self): # real signature unknown; restored from __doc__
531         """
532         S.upper() -> str
533 
534         Return a copy of S converted to uppercase.
535         """
536         return ""
537 
538     def zfill(self, width): # real signature unknown; restored from __doc__
539         """
540         原来字符右对齐，不够用0补齐
541         
542         S.zfill(width) -> str
543 
544         Pad a numeric string S with zeros on the left, to fill a field
545         of the specified width. The string S is never truncated.
546         """
547         return ""
548 
549     def __add__(self, *args, **kwargs): # real signature unknown
550         """ Return self+value. """
551         pass
552 
553     def __contains__(self, *args, **kwargs): # real signature unknown
554         """ Return key in self. """
555         pass
556 
557     def __eq__(self, *args, **kwargs): # real signature unknown
558         """ Return self==value. """
559         pass
560 
561     def __format__(self, format_spec): # real signature unknown; restored from __doc__
562         """
563         S.__format__(format_spec) -> str
564 
565         Return a formatted version of S as described by format_spec.
566         """
567         return ""
568 
569     def __getattribute__(self, *args, **kwargs): # real signature unknown
570         """ Return getattr(self, name). """
571         pass
572 
573     def __getitem__(self, *args, **kwargs): # real signature unknown
574         """ Return self[key]. """
575         pass
576 
577     def __getnewargs__(self, *args, **kwargs): # real signature unknown
578         pass
579 
580     def __ge__(self, *args, **kwargs): # real signature unknown
581         """ Return self>=value. """
582         pass
583 
584     def __gt__(self, *args, **kwargs): # real signature unknown
585         """ Return self>value. """
586         pass
587 
588     def __hash__(self, *args, **kwargs): # real signature unknown
589         """ Return hash(self). """
590         pass
591 
592     def __init__(self, value='', encoding=None, errors='strict'): # known special case of str.__init__
593         """
594         str(object='') -> str
595         str(bytes_or_buffer[, encoding[, errors]]) -> str
596 
597         Create a new string object from the given object. If encoding or
598         errors is specified, then the object must expose a data buffer
599         that will be decoded using the given encoding and error handler.
600         Otherwise, returns the result of object.__str__() (if defined)
601         or repr(object).
602         encoding defaults to sys.getdefaultencoding().
603         errors defaults to 'strict'.
604         # (copied from class doc)
605         """
606         pass
607 
608     def __iter__(self, *args, **kwargs): # real signature unknown
609         """ Implement iter(self). """
610         pass
611 
612     def __len__(self, *args, **kwargs): # real signature unknown
613         """ Return len(self). """
614         pass
615 
616     def __le__(self, *args, **kwargs): # real signature unknown
617         """ Return self<=value. """
618         pass
619 
620     def __lt__(self, *args, **kwargs): # real signature unknown
621         """ Return self<value. """
622         pass
623 
624     def __mod__(self, *args, **kwargs): # real signature unknown
625         """ Return self%value. """
626         pass
627 
628     def __mul__(self, *args, **kwargs): # real signature unknown
629         """ Return self*value.n """
630         pass
631 
632     @staticmethod # known case of __new__
633     def __new__(*args, **kwargs): # real signature unknown
634         """ Create and return a new object.  See help(type) for accurate signature. """
635         pass
636 
637     def __ne__(self, *args, **kwargs): # real signature unknown
638         """ Return self!=value. """
639         pass
640 
641     def __repr__(self, *args, **kwargs): # real signature unknown
642         """ Return repr(self). """
643         pass
644 
645     def __rmod__(self, *args, **kwargs): # real signature unknown
646         """ Return value%self. """
647         pass
648 
649     def __rmul__(self, *args, **kwargs): # real signature unknown
650         """ Return self*value. """
651         pass
652 
653     def __sizeof__(self): # real signature unknown; restored from __doc__
654         """ S.__sizeof__() -> size of S in memory, in bytes """
655         pass
656 
657     def __str__(self, *args, **kwargs): # real signature unknown
658         """ Return str(self). """
659         pass
660 
661 字符串工厂函数
662 
663 字符串工厂函数

View Code

2.2.2.4 常用举例

s.strip()
s.split()
s.find() #搜索，索引或-1
s.index() #搜索，但是报错
s.count()
s.replace()
s.startwith()
s.endwith()
s.isdigit()
s[1:5：2]

# -*-coding:UTF-8-*-



# 字符串：
#补充
# x='a' #x=str('a')  字符串操作本质上都是调用str（）
# x.replace ===>  str.replace()

'''
#字符串类型：引号包含的都是字符串类型
#需要掌握的常用操作：

msg='hello'
移除空白 msg.strip()
分割msg.split('|')
长度len(msg)
索引msg[3] msg[-1]
切片msg[0:5:2]  #0  2  4
'''

# 字符串
# s='hello world'
# s1="hello world"
# s2="""hello world"""
# s3='''hello world'''
# print(type(s))
# print(type(s1))
# print(type(s2))
# print(type(s3))

'''
# x='*****egon********'
# x=x.strip()      #strip()方法用于移除字符串头尾指定的字符（默认为空格）。
# print(x)
# print(x.strip('*'))
'''

#首字母大写
# x='hello'
# print(x.capitalize())

'''
#所有字母大写
# x='hello'
# print(x.upper())
'''

# #居中显示
# x='hello'
# print(x.center(30,'#'))

'''
#统计某个字符的长度，空格也算字符
# x='hel lo love'
# print(x.count('l'))
# print(x.count('l',0,4)) # 0 1 2 3
'''

# x='hello '                #开始的字符、末尾的字符分别是什么
# print(x.endswith(' '))
# print(x.startswith('h'))

'''
# x='hello '                #find() 方法检测字符串中是否包含子字符串 str ，
# print(x.find('e'))        #如果指定 beg（开始） 和 end（结束） 范围，则检查是否包含在指定范围内，
# print(x.find('l'))        #如果包含子字符串返回开始的索引值，否则返回-1。
'''

# 格式化字符串
# msg='Name:{},age:{},sex:{}'
# print(msg) #Name:{},age:{},sex:{}
# print(msg.format('egon',18,'male'))

# msg='Name:{0},age:{1},sex:{0}'
# print(msg.format('aaaaaaaaaaaaaaaaa','bbbbbbbbbbbbbb'))

# msg='Name:{x},age:{y},sex:{z}'
# print(msg.format(y=18,x='egon',z='male'))


'''
# x='hello world'
# print(x[0])
# print(x[4])
# print(x[5])
# print(x[100]) #报错

# print(x[-1])
# print(x[-3])
# print(x[1:3])
# print(x[1:5:2])   #始 末 步长
'''

# x='hello'                  #方法检测字符串中是否包含子字符串 str ，
# print(x.index('o'))        #如果指定 beg（开始） 和 end（结束） 范围，则检查是否包含在指定范围内，
# print(x[4])                #该方法与 python find()方法一样，只不过如果str不在 string中会报一个异常。
# print(x[x.index('o')])

'''
# x='123'
# print(x.isdigit())         #检测字符串是否只由数字组成。
#
# age=input('age: ')
# if age.isdigit():
#     new_age=int(age)
#     print(new_age,type(new_age))
'''


# msg='hello alex'
# print(msg.replace('x','X'))
# print(msg.replace('alex','SB'))
# print(msg.replace('l','A'))
# print(msg.replace('l','A',1))    #替换一个
# print(msg.replace('l','A',2))    #替换两个

'''
# x='hello          world alex SB'
# x='root:x:0:0::/root:/bin/bash'
# print(x.split(':'))
# split()通过指定分隔符对字符串进行切片，如果参数num 有指定值，则仅分隔 num 个子字符串
# 语法：str.split(str="", num=string.count(str)).
# num是指切几次，切出几个
'''

# x='hello'
# # print(x.upper())    #全部变成大写
# x='H'
# print(x.isupper())    #是否是大写
# x='HELLO'
# print(x.islower())    #是否是小写
# print(x.lower())      #全部变成小写

# x='     '
# print(x.isspace())    #是否全是空格

# msg='Hello'
# msg='hEEEE'
# print(msg.istitle())   #首字母大写/字符串中所有的单词拼写首字母是否为大写，且其他字母为小写。
#
# x='hello'
# print(x.title())       #首字母大写

# x='abc'
# print(x.ljust(10,'*'))
# print(x.rjust(10,'*'))
# ljust() 方法返回一个原字符串左对齐,并使用空格填充至指定长度的新字符串。如果指定的长度小于原字符串的长度则返回原字符串。
# 语法：str.ljust(width[, fillchar])
# rjust是右对齐

# x='Ab'
# print(x.swapcase())   #对字符串的大小写字母进行转换。

View Code

2.2.3 列表

列表之间可以比较大小，从第一个元素开始比较，只要这个元素能够分出大小就结束

定义：[]内以逗号分隔，按照索引，存放各种数据类型，每个位置代表一个元素
特性：
1.可存放多个值
2.可修改指定索引位置对应的值，可变
3.按照从左到右的顺序定义列表元素，下标从0开始顺序访问，有序

2.2.3.1 列表创建

list_test=[’lhf‘,12,'ok']
或
list_test=list('abc')
或
list_test=list([’lhf‘,12,'ok'])

2.2.3.2 列表常用操作

索引
切片
追加
删除
长度
切片
循环
包含

2.2.4 元组

定义：与列表类似，只不过［］改成（）
特性：

1.可存放多个值
2.不可变
3.按照从左到右的顺序定义元组元素，下标从0开始顺序访问，有序

2.2.4.1 元组创建

ages = (11, 22, 33, 44, 55)
或
ages = tuple((11, 22, 33, 44, 55))

2.2.4.2 元组常用操作

索引
切片
循环
长度
包含

2.2.4.3 元组工厂函数tuple()

2.2.5 字典

定义：｛key1:value1,key2:value2｝,key-value结构，key必须可hash
特性：

1.可存放多个值
2.可修改指定key对应的值，可变
3.无序

2.2.5.1 字典创建

person = {"name": "sb", 'age': 18}
或
person = dict(name='sb', age=18)
person = dict({"name": "sb", 'age': 18})
person = dict((['name','sb'],['age',18]))
{}.fromkeys(seq,100) #不指定100默认为None
注意：

>>> dic={}.fromkeys(['k1','k2'],[])
>>> dic
{'k1': [], 'k2': []}
>>> dic['k1'].append(1)
>>> dic
{'k1': [1], 'k2': [1]}

2.2.5.2 字典常用操作

索引
新增
删除
键、值、键值对
循环
长度

2.2.5.3 字典工厂函数dict()

2.2.6 集合

定义：由不同元素组成的集合，集合中是一组无序排列的可hash值，可以作为字典的key
特性：
1.集合的目的是将不同的值存放到一起，不同的集合间用来做关系运算，无需纠结于集合中单个值

2.2.6.1 集合创建

{1,2,3,1}
或
定义可变集合set
>>> set_test=set('hello')
>>> set_test
{'l', 'o', 'e', 'h'}
改为不可变集合frozenset
>>> f_set_test=frozenset(set_test)
>>> f_set_test
frozenset({'l', 'e', 'h', 'o'})

2.2.6.2 集合常用操作：关系运算

　　 in
    not in
    ＝＝
    ！＝
    <,<=
    >,>=
    |,|=:合集
    &.&=:交集
    －,－=:差集
    ^,^=:对称差分

2.2.7 bytes类型

定义：存8bit整数，数据基于网络传输或内存变量存储到硬盘时需要转成bytes类型,字符串前置b代表为bytes类型

>>> x
'hello sb'
>>> x.encode('gb2312')
b'hello sb'

2.2.8 数据类型转换内置函数汇总