Python从入门到精通_第1课_入门基础_笔记

Dear 丶 2021-11-17 23:16 336阅读 0赞

### 文章目录 ###

*  Python简介
 *  为什么选择Python
 *  环境搭建
 *  如何学好编程
 *  常用关键字
 *  基本运算符
 *  基本语法

GitHub: [https://github.com/RealEmperor/Basic-Introductory-Python-Course][https_github.com_RealEmperor_Basic-Introductory-Python-Course]

# Python简介 #

Python 是一种易于学习又功能强大的编程语言。它提供了高效的高级数据结构，还有简单有效的面向对象编程。Python 优雅的语法和动态类型，以及解释型语言的本质，使它成为多数平台上写脚本和快速开发应用的理想语言。

Python 解释器及丰富的标准库以源码或机器码的形式提供，可以到 Python 官网 [https://www.python.org/][https_www.python.org] 免费获取适用于各个主要系统平台的版本，并可自由地分发。这个网站还包含许多免费第三方 Python 模块、程序和工具以及附加文档的发布页面或链接。

Python 解释器易于扩展，可以使用 C 或 C++（或者其他可以通过 C 调用的语言）扩展新的功能和数据类型。Python 也可用于可定制化软件中的扩展程序语言。  
来源：[https://docs.python.org/zh-cn/3/tutorial/index.html][https_docs.python.org_zh-cn_3_tutorial_index.html]

# 为什么选择Python #

Python很强大（略）

# 环境搭建 #

推荐使用安装Anaconda,大部分我们要用到的库都有了，官网：[https://www.anaconda.com/][https_www.anaconda.com]

IDE推荐使用PyCharm，具体的安装办法网上很多。

# 如何学好编程 #

仁者见仁智者见智，多看，多写

最新的Python中文文档在这里：  
[https://docs.python.org/zh-cn/3/][https_docs.python.org_zh-cn_3]

# 常用关键字 #

help("keywords")

Here is a list of the Python keywords.  Enter any keyword to get more help.
    
    False               def                 if                  raise
    None                del                 import              return
    True                elif                in                  try
    and                 else                is                  while
    as                  except              lambda              with
    assert              finally             nonlocal            yield
    break               for                 not                 
    class               from                or                  
    continue            global              pass

help(\[object\])  
启动内置的帮助系统（此函数主要在交互式中使用）。如果没有实参，解释器控制台里会启动交互式帮助系统。如果实参是一个字符串，则在模块、函数、类、方法、关键字或文档主题中搜索该字符串，并在控制台上打印帮助信息。如果实参是其他任意对象，则会生成该对象的帮助页。  
来源：[https://docs.python.org/zh-cn/3/library/functions.html\#help][https_docs.python.org_zh-cn_3_library_functions.html_help]

# help的更多例子：
    # 查看Python所有的modules：
    help('modules')

# 查看Python中的topics：
    help('topics')

Here is a list of available topics.  Enter any topic name to get more help.
    
    ASSERTION           DELETION            LOOPING             SHIFTING
    ASSIGNMENT          DICTIONARIES        MAPPINGMETHODS      SLICINGS
    ATTRIBUTEMETHODS    DICTIONARYLITERALS  MAPPINGS            SPECIALATTRIBUTES
    ATTRIBUTES          DYNAMICFEATURES     METHODS             SPECIALIDENTIFIERS
    AUGMENTEDASSIGNMENT ELLIPSIS            MODULES             SPECIALMETHODS
    BASICMETHODS        EXCEPTIONS          NAMESPACES          STRINGMETHODS
    BINARY              EXECUTION           NONE                STRINGS
    BITWISE             EXPRESSIONS         NUMBERMETHODS       SUBSCRIPTS
    BOOLEAN             FLOAT               NUMBERS             TRACEBACKS
    CALLABLEMETHODS     FORMATTING          OBJECTS             TRUTHVALUE
    CALLS               FRAMEOBJECTS        OPERATORS           TUPLELITERALS
    CLASSES             FRAMES              PACKAGES            TUPLES
    CODEOBJECTS         FUNCTIONS           POWER               TYPEOBJECTS
    COMPARISON          IDENTIFIERS         PRECEDENCE          TYPES
    COMPLEX             IMPORTING           PRIVATENAMES        UNARY
    CONDITIONAL         INTEGER             RETURNING           UNICODE
    CONTEXTMANAGERS     LISTLITERALS        SCOPING             
    CONVERSIONS         LISTS               SEQUENCEMETHODS     
    DEBUGGING           LITERALS            SEQUENCES

# 查看Python所有的modules中包含指定字符串的modules：
    help("modules zlib")

Here is a list of modules whose name or summary contains 'zlib'.
    If there are any, enter a module name to get more help.
    
    zlib - The functions in this module allow compression and decompression using the
    encodings.zlib_codec - Python 'zlib_codec' Codec - zlib compression encoding.
    test.test_zlib

# 查看Python库中的module：
    import time
    help(time)

Help on built-in module time:
    
    NAME
        time - This module provides various functions to manipulate time values.
    
    DESCRIPTION
        There are two standard representations of time.  One is the number
        of seconds since the Epoch, in UTC (a.k.a. GMT).  It may be an integer
        or a floating point number (to represent fractions of seconds).
        The Epoch is system-defined; on Unix, it is generally January 1st, 1970.
        The actual value can be retrieved by calling gmtime(0).
        
        The other representation is a tuple of 9 integers giving local time.
        The tuple items are:
          year (including century, e.g. 1998)
          month (1-12)
          day (1-31)
          hours (0-23)
          minutes (0-59)
          seconds (0-59)
          weekday (0-6, Monday is 0)
          Julian day (day in the year, 1-366)
          DST (Daylight Savings Time) flag (-1, 0 or 1)
        If the DST flag is 0, the time is given in the regular time zone;
        if it is 1, the time is given in the DST time zone;
        if it is -1, mktime() should guess based on the date and time.
        
        Variables:
        
        timezone -- difference in seconds between UTC and local standard time
        altzone -- difference in  seconds between UTC and local DST time
        daylight -- whether local time should reflect DST
        tzname -- tuple of (standard time zone name, DST time zone name)
        
        Functions:
        
        time() -- return current time in seconds since the Epoch as a float
        clock() -- return CPU time since process start as a float
        sleep() -- delay for a number of seconds given as a float
        gmtime() -- convert seconds since Epoch to UTC tuple
        localtime() -- convert seconds since Epoch to local time tuple
        asctime() -- convert time tuple to string
        ctime() -- convert time in seconds to string
        mktime() -- convert local time tuple to seconds since Epoch
        strftime() -- convert time tuple to string according to format specification
        strptime() -- parse string to time tuple according to format specification
        tzset() -- change the local timezone
    
    CLASSES
        builtins.tuple(builtins.object)
            struct_time
        
        class struct_time(builtins.tuple)
         |  The time value as returned by gmtime(), localtime(), and strptime(), and
         |  accepted by asctime(), mktime() and strftime().  May be considered as a
         |  sequence of 9 integers.
         |  
         |  Note that several fields' values are not the same as those defined by
         |  the C language standard for struct tm.  For example, the value of the
         |  field tm_year is the actual year, not year - 1900.  See individual
         |  fields' descriptions for details.
         |  
         |  Method resolution order:
         |      struct_time
         |      builtins.tuple
         |      builtins.object
         |  
         |  Methods defined here:
         |  
         |  __new__(*args, **kwargs) from builtins.type
         |      Create and return a new object.  See help(type) for accurate signature.
         |  
         |  __reduce__(...)
         |      helper for pickle
         |  
         |  __repr__(self, /)
         |      Return repr(self).
         |  
         |  ----------------------------------------------------------------------
         |  Data descriptors defined here:
         |  
         |  tm_gmtoff
         |      offset from UTC in seconds
         |  
         |  tm_hour
         |      hours, range [0, 23]
         |  
         |  tm_isdst
         |      1 if summer time is in effect, 0 if not, and -1 if unknown
         |  
         |  tm_mday
         |      day of month, range [1, 31]
         |  
         |  tm_min
         |      minutes, range [0, 59]
         |  
         |  tm_mon
         |      month of year, range [1, 12]
         |  
         |  tm_sec
         |      seconds, range [0, 61])
         |  
         |  tm_wday
         |      day of week, range [0, 6], Monday is 0
         |  
         |  tm_yday
         |      day of year, range [1, 366]
         |  
         |  tm_year
         |      year, for example, 1993
         |  
         |  tm_zone
         |      abbreviation of timezone name
         |  
         |  ----------------------------------------------------------------------
         |  Data and other attributes defined here:
         |  
         |  n_fields = 11
         |  
         |  n_sequence_fields = 9
         |  
         |  n_unnamed_fields = 0
         |  
         |  ----------------------------------------------------------------------
         |  Methods inherited from builtins.tuple:
         |  
         |  __add__(self, value, /)
         |      Return self+value.
         |  
         |  __contains__(self, key, /)
         |      Return key in self.
         |  
         |  __eq__(self, value, /)
         |      Return self==value.
         |  
         |  __ge__(self, value, /)
         |      Return self>=value.
         |  
         |  __getattribute__(self, name, /)
         |      Return getattr(self, name).
         |  
         |  __getitem__(self, key, /)
         |      Return self[key].
         |  
         |  __getnewargs__(...)
         |  
         |  __gt__(self, value, /)
         |      Return self>value.
         |  
         |  __hash__(self, /)
         |      Return hash(self).
         |  
         |  __iter__(self, /)
         |      Implement iter(self).
         |  
         |  __le__(self, value, /)
         |      Return self<=value.
         |  
         |  __len__(self, /)
         |      Return len(self).
         |  
         |  __lt__(self, value, /)
         |      Return self<value.
         |  
         |  __mul__(self, value, /)
         |      Return self*value.n
         |  
         |  __ne__(self, value, /)
         |      Return self!=value.
         |  
         |  __rmul__(self, value, /)
         |      Return self*value.
         |  
         |  count(...)
         |      T.count(value) -> integer -- return number of occurrences of value
         |  
         |  index(...)
         |      T.index(value, [start, [stop]]) -> integer -- return first index of value.
         |      Raises ValueError if the value is not present.
    
    FUNCTIONS
        asctime(...)
            asctime([tuple]) -> string
            
            Convert a time tuple to a string, e.g. 'Sat Jun 06 16:26:11 1998'.
            When the time tuple is not present, current time as returned by localtime()
            is used.
        
        clock(...)
            clock() -> floating point number
            
            Return the CPU time or real time since the start of the process or since
            the first call to clock().  This has as much precision as the system
            records.
        
        ctime(...)
            ctime(seconds) -> string
            
            Convert a time in seconds since the Epoch to a string in local time.
            This is equivalent to asctime(localtime(seconds)). When the time tuple is
            not present, current time as returned by localtime() is used.
        
        get_clock_info(...)
            get_clock_info(name: str) -> dict
            
            Get information of the specified clock.
        
        gmtime(...)
            gmtime([seconds]) -> (tm_year, tm_mon, tm_mday, tm_hour, tm_min,
                                   tm_sec, tm_wday, tm_yday, tm_isdst)
            
            Convert seconds since the Epoch to a time tuple expressing UTC (a.k.a.
            GMT).  When 'seconds' is not passed in, convert the current time instead.
            
            If the platform supports the tm_gmtoff and tm_zone, they are available as
            attributes only.
        
        localtime(...)
            localtime([seconds]) -> (tm_year,tm_mon,tm_mday,tm_hour,tm_min,
                                      tm_sec,tm_wday,tm_yday,tm_isdst)
            
            Convert seconds since the Epoch to a time tuple expressing local time.
            When 'seconds' is not passed in, convert the current time instead.
        
        mktime(...)
            mktime(tuple) -> floating point number
            
            Convert a time tuple in local time to seconds since the Epoch.
            Note that mktime(gmtime(0)) will not generally return zero for most
            time zones; instead the returned value will either be equal to that
            of the timezone or altzone attributes on the time module.
        
        monotonic(...)
            monotonic() -> float
            
            Monotonic clock, cannot go backward.
        
        perf_counter(...)
            perf_counter() -> float
            
            Performance counter for benchmarking.
        
        process_time(...)
            process_time() -> float
            
            Process time for profiling: sum of the kernel and user-space CPU time.
        
        sleep(...)
            sleep(seconds)
            
            Delay execution for a given number of seconds.  The argument may be
            a floating point number for subsecond precision.
        
        strftime(...)
            strftime(format[, tuple]) -> string
            
            Convert a time tuple to a string according to a format specification.
            See the library reference manual for formatting codes. When the time tuple
            is not present, current time as returned by localtime() is used.
            
            Commonly used format codes:
            
            %Y  Year with century as a decimal number.
            %m  Month as a decimal number [01,12].
            %d  Day of the month as a decimal number [01,31].
            %H  Hour (24-hour clock) as a decimal number [00,23].
            %M  Minute as a decimal number [00,59].
            %S  Second as a decimal number [00,61].
            %z  Time zone offset from UTC.
            %a  Locale's abbreviated weekday name.
            %A  Locale's full weekday name.
            %b  Locale's abbreviated month name.
            %B  Locale's full month name.
            %c  Locale's appropriate date and time representation.
            %I  Hour (12-hour clock) as a decimal number [01,12].
            %p  Locale's equivalent of either AM or PM.
            
            Other codes may be available on your platform.  See documentation for
            the C library strftime function.
        
        strptime(...)
            strptime(string, format) -> struct_time
            
            Parse a string to a time tuple according to a format specification.
            See the library reference manual for formatting codes (same as
            strftime()).
            
            Commonly used format codes:
            
            %Y  Year with century as a decimal number.
            %m  Month as a decimal number [01,12].
            %d  Day of the month as a decimal number [01,31].
            %H  Hour (24-hour clock) as a decimal number [00,23].
            %M  Minute as a decimal number [00,59].
            %S  Second as a decimal number [00,61].
            %z  Time zone offset from UTC.
            %a  Locale's abbreviated weekday name.
            %A  Locale's full weekday name.
            %b  Locale's abbreviated month name.
            %B  Locale's full month name.
            %c  Locale's appropriate date and time representation.
            %I  Hour (12-hour clock) as a decimal number [01,12].
            %p  Locale's equivalent of either AM or PM.
            
            Other codes may be available on your platform.  See documentation for
            the C library strftime function.
        
        time(...)
            time() -> floating point number
            
            Return the current time in seconds since the Epoch.
            Fractions of a second may be present if the system clock provides them.
    
    DATA
        altzone = -32400
        daylight = 0
        timezone = -28800
        tzname = ('ÖÐ¹ú±ê×¼Ê±¼ä', 'ÖÐ¹úÏÄÁîÊ±')
    
    FILE
        (built-in)

help('time')  # 字符串和上面效果一致

# 基本运算符 #

以下形符属于运算符:

\+ - \* \*\* / // % @  
<< >> & | ^ ~  
< > <= >= == !=

\#分隔符

以下形符在语法中归类为分隔符:

( ) \[ \] \{ \}  
, : . ; @ = ->  
\+= -= \*= /= //= %= @=  
&= |= ^= >>= <<= \*\*=

句点也可出现于浮点数和虚数字面值中。连续三个句点有表示一个省略符的特殊含义。以上列表的后半部分为增强赋值操作符，在词法中作为分隔符，但也起到运算作用。

以下可打印 ASCII 字符作为其他形符的组成部分时具有特殊含义，或是对词法分析器有重要意义:

’ " \# \\

以下可打印 ASCII 字符不在 Python 词法中使用。如果出现于字符串字面值和注释之外将无条件地引发错误:

$ ? \`

来源：[https://docs.python.org/zh-cn/3/reference/lexical\_analysis.html\#operators][https_docs.python.org_zh-cn_3_reference_lexical_analysis.html_operators]

# 基本语法 #

跟着文档一步步学就可以了 [https://docs.python.org/zh-cn/3/tutorial/index.html][https_docs.python.org_zh-cn_3_tutorial_index.html]

这不再赘述

[https_github.com_RealEmperor_Basic-Introductory-Python-Course]: https://github.com/RealEmperor/Basic-Introductory-Python-Course
[https_www.python.org]: https://www.python.org/
[https_docs.python.org_zh-cn_3_tutorial_index.html]: https://docs.python.org/zh-cn/3/tutorial/index.html
[https_www.anaconda.com]: https://www.anaconda.com/
[https_docs.python.org_zh-cn_3]: https://docs.python.org/zh-cn/3/
[https_docs.python.org_zh-cn_3_library_functions.html_help]: https://docs.python.org/zh-cn/3/library/functions.html#help
[https_docs.python.org_zh-cn_3_reference_lexical_analysis.html_operators]: https://docs.python.org/zh-cn/3/reference/lexical_analysis.html#operators