郭進電腦使用筆記: Python 基本操作

python IDEL

alt + / 自動完成單詞(可重複循循) Expand Word

alt + p 重複上一次操作 Previous Command

alt + n 下一個指令 Next Command

help([object]) 列出(指令的)說明文件

dir([object]) 列出object下面的所有屬性及方法

dir() help()

**********************************************201207*

Python 3.9.5 (tags/v3.9.5:0a7dcbd, May 3 2021, 17:27:52) [MSC v.1928 64 bit (AMD64)] on win32

Type "help", "copyright", "credits" or "license()" for more information.

>>>

---------------------------------------------------------內建涵式或物件

lst=dir(__builtins__)

len(lst)
159

lst.index("abs")
84

for i in range(84,len(lst)):
    print("{0:12s}".format(lst[i]),end=" ")
    if (i-83)%10==0:print()


abs          aiter        all          anext        any          ascii        bin          bool         breakpoint   bytearray
bytes        callable     chr          classmethod compile      complex      copyright    credits      delattr      dict
dir          divmod       enumerate    eval         exec         exit         filter       float        format       frozenset
getattr      globals      hasattr      hash         help         hex          id           input        int          isinstance
issubclass   iter         len          license      list         locals       map          max          memoryview   min
next         object       oct          open         ord          pow          print        property     quit         range
repr         reversed     round        set          setattr      slice        sorted       staticmethod str          sum
super        tuple        type         vars         zip

------------------------------------------------------涵式使用方式與說明

dir(list)
['__add__', '__class__', '__class_getitem__', '__contains__', '__delattr__', '__delitem__', '__dir__', '__doc__', '__eq__', '__format__', '__ge__', '__getattribute__', '__getitem__', '__getstate__', '__gt__', '__hash__', '__iadd__', '__imul__', '__init__', '__init_subclass__', '__iter__', '__le__', '__len__', '__lt__', '__mul__', '__ne__', '__new__', '__reduce__', '__reduce_ex__', '__repr__', '__reversed__', '__rmul__', '__setattr__', '__setitem__', '__sizeof__', '__str__', '__subclasshook__', 'append', 'clear', 'copy', 'count', 'extend', 'index', 'insert', 'pop', 'remove', 'reverse', 'sort']

------------------------------------------------------物件的屬性與方法

help(list.append)
Help on method_descriptor:

append(self, object, /)
Append object to the end of the list.

---------------------------------------------------------ASCII

Dec   控制動作
0   空字元 Null character
1   標題開始 Start of heading
2   本文開始 Start of text
3   本文結束 End of text
4   傳輸結束 End of Submission, 不同於 ETB
5   請求查詢 Enquiry, 與 ACK 一起使用
6   確認回應 Acknowledge, 清除 ENQ 請求查詢
7   鈴聲 Bell, Rings Bell...
8   退格 Backspace, Delete 刪除字元鍵
9   水平定位符號 Tab 空格鍵 Horizontal tab
10   換行鍵 Line Feed CHR(10)
11   直定位符號 Vertical tab
12   換頁鍵 Form Feed, page eject
13   回車 [Enter] Carriage Return CHR(13)
14   取消變換 Shift Out, 替代字符集
15   啟用變換 Shift In, 恢復默認字符集
16   跳出資料通訊 Data link escape
17   設備控制一 Device control 1 (XON)
18   設備控制二 Device control 2
19   設備控制三 Device control 3 (XOFF)
20   設備控制四 Device control 4
21   否定失敗回應 Negative acknowledge
22   同步用暫停 Synchronous idle
23   區塊傳輸結束 End Submission block, 與 EOT 不同
24   取消 Cancel line
25   連線媒介中斷 End of medium, Ctrl + Y 中斷
26   替代字符 Substitute
27   退出鍵 Escape, Esc
28   檔案分割符 File Separator
29   群組分隔符 Group Separator
30   記錄分隔符 Record Separator, 塊模終止符
31   單元分隔符 Unit Separator
32   Space

...

127 Delete (rubout), cross-hatch box

for i in range(33,126+1):
print("i={0:3d}-->{1:1s} ".format(i,chr(i)),end="\t")
if (i-32)%7==0:print()

i= 33-->!     i= 34-->"     i= 35-->#     i= 36-->$     i= 37-->%     i= 38-->&     i= 39-->'
i= 40-->(     i= 41-->)     i= 42-->*     i= 43-->+     i= 44-->,     i= 45-->-     i= 46-->.
i= 47-->/     i= 48-->0     i= 49-->1     i= 50-->2     i= 51-->3     i= 52-->4     i= 53-->5
i= 54-->6     i= 55-->7     i= 56-->8     i= 57-->9     i= 58-->:     i= 59-->;     i= 60--><
i= 61-->=     i= 62-->>     i= 63-->?     i= 64-->@     i= 65-->A     i= 66-->B     i= 67-->C
i= 68-->D     i= 69-->E     i= 70-->F     i= 71-->G     i= 72-->H     i= 73-->I     i= 74-->J
i= 75-->K     i= 76-->L     i= 77-->M     i= 78-->N     i= 79-->O     i= 80-->P     i= 81-->Q
i= 82-->R     i= 83-->S     i= 84-->T     i= 85-->U     i= 86-->V     i= 87-->W     i= 88-->X
i= 89-->Y     i= 90-->Z     i= 91-->[     i= 92-->\     i= 93-->]     i= 94-->^     i= 95-->_
i= 96-->`     i= 97-->a     i= 98-->b     i= 99-->c     i=100-->d     i=101-->e     i=102-->f
i=103-->g     i=104-->h     i=105-->i     i=106-->j     i=107-->k     i=108-->l     i=109-->m
i=110-->n     i=111-->o     i=112-->p     i=113-->q     i=114-->r     i=115-->s     i=116-->t
i=117-->u     i=118-->v     i=119-->w     i=120-->x     i=121-->y     i=122-->z     i=123-->{
i=124-->|     i=125-->}     i=126-->~

------------------------------------------------------help()

>>> help()

Welcome to Python 3.9's help utility!

...

To quit this help utility and return to the interpreter, just type "quit".

...

-----------------------------------pyhton 關鍵字

help> keywords

Here is a list of the Python keywords. Enter any keyword to get more help.

False break for not

None class from or

True continue global pass

__peg_parser__ def if raise

and del import return

as elif in try

assert else is while

async except lambda with

await finally nonlocal yield

-----------------------------------pyhton 模組

help> modules

Please wait a moment while I gather a list of all available modules...

__future__ argparse help sched

__main__ array help_about scrolledlist

_abc ast history search

_aix_support asynchat hmac searchbase

_ast asyncio html searchengine

_asyncio asyncore http secrets

_bisect atexit hyperparser select

_blake2 audioop idle selectors

_bootlocale autocomplete idle_test setuptools

_bootsubprocess autocomplete_w idlelib shelve

_bz2 autoexpand imaplib shlex

_codecs autopep8 imghdr shutil

_codecs_cn base64 imp sidebar

_codecs_hk bdb importlib signal

_codecs_iso2022 binascii inspect site

_codecs_jp binhex io smtpd

_codecs_kr bisect iomenu smtplib

_codecs_tw browser ipaddress sndhdr

_collections builtins itertools socket

_collections_abc bz2 json socketserver

_compat_pickle cProfile keyword sqlite3

_compression calendar lib2to3 squeezer

_contextvars calltip linecache sre_compile

_csv calltip_w locale sre_constants

_ctypes cgi logging sre_parse

_ctypes_test cgitb lzma ssl

_datetime chunk macosx stackviewer

_decimal cmath mailbox stat

_distutils_hack cmd mailcap statistics

_elementtree code mainmenu statusbar

_functools codecontext marshal string

_hashlib codecs math stringprep

_heapq codeop mimetypes struct

_imp collections mmap subprocess

_io colorizer modulefinder sunau

_json colorsys msilib symbol

_locale compileall msvcrt symtable

_lsprof concurrent multicall sys

_lzma config multiprocessing sysconfig

_markupbase config_key netrc tabnanny

_md5 configdialog nntplib tarfile

_msi configparser nt telnetlib

_multibytecodec contextlib ntpath tempfile

_multiprocessing contextvars nturl2path test

_opcode copy numbers textview

_operator copyreg opcode textwrap

_osx_support crypt operator this

_overlapped csv optparse threading

_peg_parser ctypes os time

_pickle curses outwin timeit

_py_abc dataclasses parenmatch tkinter

_pydecimal datetime parser token

_pyio dbm pathbrowser tokenize

_queue debugger pathlib toml

_random debugger_r pdb tooltip

_sha1 debugobj percolator trace

_sha256 debugobj_r pickle traceback

_sha3 decimal pickletools tracemalloc

_sha512 delegator pip tree

_signal difflib pipes tty

_sitebuiltins dis pkg_resources turtle

_socket distutils pkgutil turtledemo

_sqlite3 doctest platform types

_sre dynoption plistlib typing

_ssl editor poplib undo

_stat email posixpath unicodedata

_statistics encodings pprint unittest

_string ensurepip profile urllib

_strptime enum pstats uu

_struct errno pty uuid

_symtable faulthandler py_compile venv

_testbuffer filecmp pyclbr warnings

_testcapi fileinput pycodestyle wave

_testconsole filelist pydoc weakref

_testimportmultiple fnmatch pydoc_data webbrowser

_testinternalcapi format pyexpat window

_testmultiphase formatter pyparse winreg

_thread fractions pyshell winsound

_threading_local ftplib query wsgiref

_tkinter functools queue xdrlib

_tracemalloc gc quopri xml

_uuid genericpath random xmlrpc

_warnings getopt re xxsubtype

_weakref getpass redirector zipapp

_weakrefset gettext replace zipfile

_winapi glob reprlib zipimport

_xxsubinterpreters graphlib rlcompleter zlib

_zoneinfo grep rpc zoneinfo

abc gzip run zoomheight

aifc hashlib runpy zzdummy

antigravity heapq runscript

---------------------

help> math

Help on built-in module math:

NAME

math

DESCRIPTION

This module provides access to the mathematical functions

defined by the C standard.

FUNCTIONS

acos(x, /)

Return the arc cosine (measured in radians) of x.

The result is between 0 and pi.

...

---------------------

help> modules math

Here is a list of modules whose name or summary contains 'math'.
If there are any, enter a module name to get more help.

cmath - This module provides access to mathematical functions for complex
math - This module provides access to the mathematical functions
math_test
math
test.test_cmath
test.test_math
PIL.ImageMath
PIL._imagingmath
django.db.models.functions.math
numpy.core._multiarray_umath
numpy.core._umath_tests
numpy.core.tests.test_scalarmath
numpy.core.tests.test_umath
numpy.core.tests.test_umath_accuracy
numpy.core.tests.test_umath_complex
numpy.core.umath - Create the numpy.core.umath namespace for backward compatibility. In v1.16
numpy.core.umath_tests - Shim for _umath_tests to allow a deprecation period for the new name.
numpy.lib.scimath - Wrapper functions to more user-friendly calling of certain math functions
numpy.linalg._umath_linalg
pygame.math
pygame.tests.math_test

import math
dir()
['__annotations__', '__builtins__', '__doc__', '__loader__', '__name__', '__package__', '__spec__', 'math']

dir(math)
['__doc__', '__loader__', '__name__', '__package__', '__spec__', 'acos', 'acosh', 'asin', 'asinh', 'atan', 'atan2', 'atanh', 'cbrt', 'ceil', 'comb', 'copysign', 'cos', 'cosh', 'degrees', 'dist', 'e', 'erf', 'erfc', 'exp', 'exp2', 'expm1', 'fabs', 'factorial', 'floor', 'fmod', 'frexp', 'fsum', 'gamma', 'gcd', 'hypot', 'inf', 'isclose', 'isfinite', 'isinf', 'isnan', 'isqrt', 'lcm', 'ldexp', 'lgamma', 'log', 'log10', 'log1p', 'log2', 'modf', 'nan', 'nextafter', 'perm', 'pi', 'pow', 'prod', 'radians', 'remainder', 'sin', 'sinh', 'sqrt', 'tan', 'tanh', 'tau', 'trunc', 'ulp']

help(math.pow)
Help on built-in function pow in module math:

pow(x, y, /)
Return x**y (x to the power of y).

help> quit

You are now leaving help and returning to the Python interpreter.

If you want to ask for help on a particular object directly from the

interpreter, you can type "help(object)". Executing "help('string')"

has the same effect as typing a particular string at the help> prompt.

>>>

------------------------------------------------------

>>> import this

The Zen of Python, by Tim Peters python 禪學

進制轉換

*******************************************

chr(65)
'A'
ord("A")
65

bin(65)
'0b1000001'
oct(65)
'0o101'
hex(65)
'0x41'

int(0b1000001)
65
int(0o101)
65
int(0x41)
65

"{0:b}".format(65)
'1000001'
"{0:o}".format(65)
'101'
"{0:x}".format(65)
'41'

"{0:d}".format(0b1000001)
'65'
"{0:d}".format(0o101)
'65'
"{0:d}".format(0x41)
'65'

format(65,"b")
'1000001'
format(65,"o")
'101'
format(65,"x")
'41'

format(0b1000001,"d")
'65'
format(0o101,"d")
'65'
format(0x41,"d")
'65'

print("%b" %(65))
Traceback (most recent call last):
File "<pyshell#39>", line 1, in <module>
print("%b" %(65))
ValueError: unsupported format character 'b' (0x62) at index 1

print("%o" %(65))
101
print("%x" %(65))
41

--------------------------------------i、d 皆代表10進制

print("%d" %(0b1000001))
65
print("%d" %(0o101))
65
print("%d" %(0x41))
65

print(f'{65:b}')
1000001
print(f'{65:o}')
101
print(f'{65:x}')
41

----------------------------10進制轉2、8、16----------------------------

bin(65)
'0b1000001'
format(65,"b")
'1000001'

#沒此用法

print("%b" %65)
Traceback (most recent call last):
File "<pyshell#59>", line 1, in <module>
print("%b" %65)
ValueError: unsupported format character 'b' (0x62) at index 1

oct(65)
'0o101'
format(65,"o")
'101'
print("%o" %65)
101

hex(65)
'0x41'
format(65,"x")
'41'
print("%x" %65)
41

----------------------------2、8、16進制轉10----------------------------

int(0b1000001)
65
int("0b1000001",2)
65
int("1000001",2)
65

int(0o101)
65
int("0o101",8)
65
int("101",8)
65

int(0x41)
65
int("0x41",16)
65
int("41",16)
65

----------------------------16進制轉2---------------------------

bin(0x41)
'0b1000001

----------------------------2進制轉16---------------------------

hex(0b1000001)
'0x41'

------------------------------------------------------10進制小數點轉2進制

def ConvertDecimalFractionToBinary(Fraction):
    x=Fraction
    RtnStr=""
    while x>0:
        x=x*2
        if x>=1:
            RtnStr=RtnStr+"1"
            x=x-1
        else:
            RtnStr=RtnStr+"0"

    return (RtnStr)

Franction=float(input("輸入任正小數："))
print(str(Franction)+"轉成二進制="+ConvertDecimalFractionToBinary(Franction))

=======

輸入任正小數：0.8125
0.8125轉成二進制=1101

def DecToBin(x):

LstBin=[]

while x:

x *=2

LstBin.append(1 if x>=1 else 0 )

x -= int(x)

return LstBin

n=0.3

print(DecToBin(n))

=========

[0, 1, 0, 0, 1, 1, 0, 0, 1, 1, 0, 0, 1, 1, 0, 0, 1, 1, 0, 0, 1, 1, 0, 0, 1, 1, 0, 0, 1, 1, 0, 0, 1, 1, 0, 0, 1, 1, 0, 0, 1, 1, 0, 0, 1, 1, 0, 0, 1, 1, 0, 0, 1, 1]

+++++++

def DecToBin(x):

LstBin=[]

while x:

x *=2

LstBin.append("1" if x>=1 else "0" )

x -= int(x)

#print(LstBin)

strBin="0."+"".join(LstBin)

return strBin

n=0.1

print(DecToBin(n))

=========

(0.1)=0.0001100110011001100110011001100110011001100110011001101 (0011循环)

(0.2)=0.001100110011001100110011001100110011001100110011001101 (0011循环)

(0.3)=0.010011001100110011001100110011001100110011001100110011 (1001循环)

(0.4)=0.01100110011001100110011001100110011001100110011001101 (0110循环)

++++++

def dec2bin(x):

x -= int(x)

bins = []

while x:

x *= 2

bins.append(1 if x>=1. else 0)

x -= int(x)

return bins

#print(dec2bin(.8125))

# [1, 1, 0, 1]

print(dec2bin(0.1))

def bin2dec(b):

d = 0

for i, x in enumerate(b):

d += 2**(-i-1)*x

return d

#print(dec2bin(0.8125))

# [1, 1, 0, 1]

#print(bin2dec(dec2bin(0.8125)))

# 0.8125

print(bin2dec(dec2bin(0.1)))

#print(bin2dec([1, 1, 0, 1]))

++++

https://segmentfault.com/a/1190000020953696

------------------------------------------------------???

for i in range(0,10+1):

print("0.1+",(i/10),"=",0.1+(i/10))

=========

0.1+ 0.0 = 0.1

0.1+ 0.1 = 0.2

0.1+ 0.2 = 0.30000000000000004

0.1+ 0.3 = 0.4

0.1+ 0.4 = 0.5

0.1+ 0.5 = 0.6

0.1+ 0.6 = 0.7

0.1+ 0.7 = 0.7999999999999999

0.1+ 0.8 = 0.9

0.1+ 0.9 = 1.0

0.1+ 1.0 = 1.1

------------------------------

>>> format(65,'b')
'1000001'
>>> format(65,'o')
'101'
>>> format(65,'x')
'41'

char to ascii

*******************************************

chr(65)

'A'

ord('A')

----------------------------

>>> print('\101') #8進制

>>> print('\x41') #16進制

------------------------------------------------------使用標準涵式庫

>>> dir()

['__annotations__', '__builtins__', '__doc__', '__loader__', '__name__', '__package__', '__spec__']

>>> import math as MT

>>> dir()

['MT', '__annotations__', '__builtins__', '__doc__', '__loader__', '__name__', '__package__', '__spec__']

>>> dir(MT)

['__doc__', '__loader__', '__name__', '__package__', '__spec__', 'acos', 'acosh', 'asin', 'asinh', 'atan', 'atan2', 'atanh', 'ceil', 'comb', 'copysign', 'cos', 'cosh', 'degrees', 'dist', 'e', 'erf', 'erfc', 'exp', 'expm1', 'fabs', 'factorial', 'floor', 'fmod', 'frexp', 'fsum', 'gamma', 'gcd', 'hypot', 'inf', 'isclose', 'isfinite', 'isinf', 'isnan', 'isqrt', 'lcm', 'ldexp', 'lgamma', 'log', 'log10', 'log1p', 'log2', 'modf', 'nan', 'nextafter', 'perm', 'pi', 'pow', 'prod', 'radians', 'remainder', 'sin', 'sinh', 'sqrt', 'tan', 'tanh', 'tau', 'trunc', 'ulp']

>>> help(MT.ceil)

Help on built-in function ceil in module math:

ceil(x, /)

Return the ceiling of x as an Integral.

This is the smallest integer >= x.

>>> for i in range(LstMath.index('acos'),len(LstMath)):

print("{0:10s}".format(LstMath[i]),end='')

acos acosh asin asinh atan atan2 atanh ceil comb copysign cos cosh degrees dist e erf erfc exp expm1 fabs factorial floor fmod frexp fsum gamma gcd hypot inf isclose isfinite isinf isnan isqrt lcm ldexp lgamma log log10 log1p log2 modf nan nextafter perm pi pow prod radians remainder sin sinh sqrt tan tanh tau trunc ulp

>>> del MT

>>> dir()

['__annotations__', '__builtins__', '__doc__', '__loader__', '__name__', '__package__', '__spec__']

對數、指數

*******************************************

10**2

100

pow(10,2)

100

math.log(100,10)

2.0

2**3

pow(2,3)

math.log(8,2)

3.0

徑度轉角度

*******************************************

弧度又叫弳度。單位弧度定義做圓弧長度(arc length)等於半徑(radius)時的圓心角。角度以弧度做單位時，通常不寫單位，有時記做rad（㎭）。一個完整圓，弧度係2π，所以2π rad = 360°

sin(30)=1/2

math.sin((30/360)*2*math.pi)

0.49999999999999994

math.pi/6

0.5235987755982988

math.radians(30)

0.5235987755982988

math.degrees(math.pi/6)

29.999999999999996

math.sin(math.radians(30))

0.49999999999999994

序列型別:

字串str、串列list、字典dict

set、tuple

*******************************************

>>> str1="HelloDay!"

>>> type(str1)

>>> for i in range(len(str1)):

print("{0:2d}={1:1s}".format(i,str1[i]),end='')

0=H 1=e 2=l 3=l 4=o 5=D 6=a 7=y 8=!

[ ] 切片 Slicing 運算

--------------------------------

>>> str1[5] //index=5

'D'

>>> str1[5:] //index=5~最後

'Day!'

>>> str1[5:7] //index=5~7 即(6+1)

'Da'

>>> str1[:] //複製

'HelloDay!'

>>> str1[::-1] //反轉

'!yaDolleH'

>>> str1[2:7:2] //index=2~(6+1) 間格2

'loa'

>>> str1[6::4] //index=6~ 間格4，不足又從index=6 開始

'a'

字串常用函式
--------------------------------

>>> str1.find('o')

>>> str1.count('l')

>>> str2=str1.replace("Day"," World")

>>> str2

'Hello World!'

>>> str1

'HelloDay!' //原字串不變

>>> str2.split() //str~list

['Hello', 'World!']

>>> str2

'Hello World!' //原字串不變

>>> str3=["Python","is","fun"]

>>> ' '.join(str3) //list~str

'Python is fun'

>>> str3

['Python', 'is', 'fun'] //原串列不變

*******************************************

>>> dictStu={'小萌': '1001', '小智': '1002', '小强': '1003', '小明': '1004'}

>>> dictStu

{'小萌': '1001', '小智': '1002', '小强': '1003', '小明': '1004'}

>>> dictStu.keys()

dict_keys(['小萌', '小智', '小强', '小明'])

>>> dictStu.values()

dict_values(['1001', '1002', '1003', '1004'])

>>> dictStu.items()

dict_items([('小萌', '1001'), ('小智', '1002'), ('小强', '1003'), ('小明', '1004')])

key --> value

-------------------------

>>> dicStu['小智']

'1002'

>>> list(dictStu.keys())

['小萌', '小智', '小强', '小明']

>>> list(dictStu.values())

['1001', '1002', '1003', '1004']

>>> list(dictStu.values()).index('1002')

value --> key

------------------------------

>>> list(dictStu.keys())[list(dictStu.values()).index('1002')]

'小智

>>> [k for k,v in dictStu.items() if v=='1002']

['小智']

反轉原dcit

>>> {v:k for k,v in dictStu.items()}['1002']

'小智'

list預設值

*******************************************

>>> Lst=[i for i in range(0,10+1) if i%2==0]

>>> Lst

[0, 2, 4, 6, 8, 10]

>>> sum(i for i in range(1,10+1))

>>> sum(i for i in range(1,10+1) if i%2==0)

>>> sum(i for i in range(1,10+1) if i%2!=0)

>>> Lst=[i for i in range(1,10+1)]

>>> print(Lst)

[1, 2, 3, 4, 5, 6, 7, 8, 9, 10]

>>> Lst=[i for i in range(1,10+1) if i%2==0]

>>> print(Lst)

[2, 4, 6, 8, 10]

Divide And Conquer:

Recursive:

1. Divide

2. Conquer

3. Combine

*******************************************

from math import floor

Recsiv=0

def conquer(Lst,PointerLeft,PointerRight):

global Recsiv

Recsiv+=1

print("Recsiv=",Recsiv," Lst=",Lst)

if PointerLeft<PointerRight:

print("PointerLeft=",PointerLeft," PointerRight=",PointerRight)

PointerMid=floor((PointerRight+PointerLeft)/2)

print("PointerMid=",PointerMid)

print()

print("Recsiv=",Recsiv," 目前Lst=",Lst[PointerLeft:PointerMid])

print()

print("Enter Recursive Again!!")

conquer(Lst,PointerLeft,PointerMid)

print("Recsiv=",Recsiv," 回上層，進入遞迴前的堆疊，繼續往下執行，Lst=",Lst[PointerLeft:PointerMid])

#print(Lst[PointerMid+1:PointerRight])

#conquer(Lst,PointerMid+1,PointerRight)

#print(Lst[PointerMid+1:PointerRight])

return Lst

else:

print("已不符遞迴條件!!")

print()

data=[50,60,45,30,90,20,80,15]

print("\nFinal Result:",conquer(data,0,8))

==========

Recsiv= 1 Lst= [50, 60, 45, 30, 90, 20, 80, 15]

PointerLeft= 0 PointerRight= 8

PointerMid= 4

Recsiv= 1 目前Lst= [50, 60, 45, 30]

Enter Recursive Again!!

Recsiv= 2 Lst= [50, 60, 45, 30, 90, 20, 80, 15]

PointerLeft= 0 PointerRight= 4

PointerMid= 2

Recsiv= 2 目前Lst= [50, 60]

Enter Recursive Again!!

Recsiv= 3 Lst= [50, 60, 45, 30, 90, 20, 80, 15]

PointerLeft= 0 PointerRight= 2

PointerMid= 1

Recsiv= 3 目前Lst= [50]

Enter Recursive Again!!

Recsiv= 4 Lst= [50, 60, 45, 30, 90, 20, 80, 15]

PointerLeft= 0 PointerRight= 1

PointerMid= 0

Recsiv= 4 目前Lst= []

Enter Recursive Again!!

Recsiv= 5 Lst= [50, 60, 45, 30, 90, 20, 80, 15]

已不符遞迴條件!!

Recsiv= 5 回上層，進入遞迴前的堆疊，繼續往下執行，Lst= []

Recsiv= 5 回上層，進入遞迴前的堆疊，繼續往下執行，Lst= [50]

Recsiv= 5 回上層，進入遞迴前的堆疊，繼續往下執行，Lst= [50, 60]

Recsiv= 5 回上層，進入遞迴前的堆疊，繼續往下執行，Lst= [50, 60, 45, 30]

Final Result: [50, 60, 45, 30, 90, 20, 80, 15]

+++++++++++++++++++++++++++++++

import math

def merge(items,p,q,r,LorR):

n1=q-p+1

n2=r-q

L=[]

R=[]

for i in range(0,n1):

L.append(items[p+i])

for j in range(0,n2):

R.append(items[q+j+1])

L.append(math.inf)

print("merge前:L=",L)

R.append(math.inf)

print("merge前:R=",R)

i=0

j=0

for k in range(p,r+1):

if L[i] <=R[j]:

items[k]=L[i]

i=i+1

else:

items[k]=R[j]

j=j+1

print("Recsiv=",Recsiv,"merge結束後，目前items=",items)

print()

Recsiv=0

def mergesort(items,p,r,LorR):

global Recsiv

Recsiv+=1

print("Recsiv=",Recsiv)

print(LorR,"mergesort...","p=",p,"r=",r)

if p<r:

q=math.floor((p+r)/2)

print("p=",p,"q=",q,"r=",r)

print("00LL=",items[p:q+1])

print("00RR=",items[q+1:r+1])

print()

mergesort(items,p,q,"左")

mergesort(items,q+1,r,"右")

print("開始merge...")

merge(items,p,q,r,LorR)

else:

print("已不符遞迴條件!")

print()

items=[5,2,9,7]

#items=[5,2,4,7,1,3,2,6]

mergesort(items,0,len(items)-1,"未分左右")

print(items)

=========

Recsiv= 1

未分左右 mergesort... p= 0 r= 3

p= 0 q= 1 r= 3

00LL= [5, 2]

00RR= [9, 7]

Recsiv= 2

左 mergesort... p= 0 r= 1

p= 0 q= 0 r= 1

00LL= [5]

00RR= [2]

Recsiv= 3

左 mergesort... p= 0 r= 0

已不符遞迴條件!

Recsiv= 4

右 mergesort... p= 1 r= 1

已不符遞迴條件!

開始merge...

merge前:L= [5, inf]

merge前:R= [2, inf]

Recsiv= 4 merge結束後，目前items= [2, 5, 9, 7]

Recsiv= 5

右 mergesort... p= 2 r= 3

p= 2 q= 2 r= 3

00LL= [9]

00RR= [7]

Recsiv= 6

左 mergesort... p= 2 r= 2

已不符遞迴條件!

Recsiv= 7

右 mergesort... p= 3 r= 3

已不符遞迴條件!

開始merge...

merge前:L= [9, inf]

merge前:R= [7, inf]

Recsiv= 7 merge結束後，目前items= [2, 5, 7, 9]

開始merge...

merge前:L= [2, 5, inf]

merge前:R= [7, 9, inf]

Recsiv= 7 merge結束後，目前items= [2, 5, 7, 9]

[2, 5, 7, 9]

Permutation

*******************************************

RecSiv=0

def perm(Lst):

global RecSiv

RecSiv+=1

if len(Lst)<=1:

return Lst

Key=Lst[0]

print("RecSiv=",RecSiv," Key=",Key)

print()

print(Lst[1:],"進入遞迴...")

print()

Remaining=perm(Lst[1:])

print("結束RecSiv=",RecSiv," 後，Remaining=",Remaining)

print()

Result=[]

for Remaining_tmp in Remaining:

for i in range(len(Remaining_tmp)+1):

print("寫入Result前， Remaining_tmp=",Remaining_tmp,"Key=",Key)

Result.append(Remaining_tmp[:i]+Key+Remaining_tmp[i:])

print("目前Result=",Result)

print()

return Result

data="ABC"

print("\n最後結果:",perm(data))

=========

RecSiv= 1 Key= A

BC 進入遞迴...

RecSiv= 2 Key= B

C 進入遞迴...

結束RecSiv= 3 後，Remaining= C

寫入Result前， Remaining_tmp= C Key= B

目前Result= ['BC']

寫入Result前， Remaining_tmp= C Key= B

目前Result= ['BC', 'CB']

結束RecSiv= 3 後，Remaining= ['BC', 'CB']

寫入Result前， Remaining_tmp= BC Key= A

目前Result= ['ABC']

寫入Result前， Remaining_tmp= BC Key= A

目前Result= ['ABC', 'BAC']

寫入Result前， Remaining_tmp= BC Key= A

目前Result= ['ABC', 'BAC', 'BCA']

寫入Result前， Remaining_tmp= CB Key= A

目前Result= ['ABC', 'BAC', 'BCA', 'ACB']

寫入Result前， Remaining_tmp= CB Key= A

目前Result= ['ABC', 'BAC', 'BCA', 'ACB', 'CAB']

寫入Result前， Remaining_tmp= CB Key= A

目前Result= ['ABC', 'BAC', 'BCA', 'ACB', 'CAB', 'CBA']

最後結果: ['ABC', 'BAC', 'BCA', 'ACB', 'CAB', 'CBA']

++++++++++++++++

Key="B"

tmp=["C"]

Result=[]

for i in tmp:

for j in range(len(tmp)+1):

print("j=",j," i[:j]=",i[:j]," Key=",Key," i[j:]=",i[j:])

Result.append(i[:j]+Key+i[j:])

print("Result=",Result)

print()

=========

j= 0 i[:j]= Key= B i[j:]= C

Result= ['BC']

j= 1 i[:j]= C Key= B i[j:]=

Result= ['BC', 'CB']

++++++++++++++++

Key="A"

tmp=["BC","CB"]

Result=[]

for i in tmp:

for j in range(len(tmp)+1):

print("j=",j," i[:j]=",i[:j]," Key=",Key," i[j:]=",i[j:])

Result.append(i[:j]+Key+i[j:])

print("Result=",Result)

print()

=========

j= 0 i[:j]= Key= A i[j:]= BC

Result= ['ABC']

j= 1 i[:j]= B Key= A i[j:]= C

Result= ['ABC', 'BAC']

j= 2 i[:j]= BC Key= A i[j:]=

Result= ['ABC', 'BAC', 'BCA']

j= 0 i[:j]= Key= A i[j:]= CB

Result= ['ABC', 'BAC', 'BCA', 'ACB']

j= 1 i[:j]= C Key= A i[j:]= B

Result= ['ABC', 'BAC', 'BCA', 'ACB', 'CAB']

j= 2 i[:j]= CB Key= A i[j:]=

Result= ['ABC', 'BAC', 'BCA', 'ACB', 'CAB', 'CBA']

Combination

*******************************************

def combine(n,k,Result,index,tmp):

print("n=",n," k=",k," Result=",Result,"index=",index,"tmp=",tmp)

print()

if len(tmp)==k:

Result.append(tmp[:])

print("---len(tmp)==k------------目前 Result=",Result)

print()

return

print("進入For 迴圈前 index=",index,"n+1=",n+1)

#print()

#1,2,3,4 ==>n+1

for i in range(index,n+1):

print("For 迴圈的 i=",i)

tmp.append(i)

print("---tmp.append(i)------------未進入combine前 tmp=",tmp)

#print()

print("---combine(n,k,Result,i+1,tmp)------------再次執行combine......")

#print()

combine(n,k,Result,i+1,tmp)

print("結束 combine 未 pop 前 tmp=",tmp)

tmp.pop()

print("結束 combine 已 pop 後 tmp=",tmp)

print()

return Result

res=combine(4,2,[],1,[])

print("FinalResult=",res)

=========

n= 4 k= 2 Result= [] index= 1 tmp= []

進入For 迴圈前 index= 1 n+1= 5

For 迴圈的 i= 1

---tmp.append(i)------------未進入combine前 tmp= [1]

---combine(n,k,Result,i+1,tmp)------------再次執行combine......

n= 4 k= 2 Result= [] index= 2 tmp= [1]

進入For 迴圈前 index= 2 n+1= 5

For 迴圈的 i= 2

---tmp.append(i)------------未進入combine前 tmp= [1, 2]

---combine(n,k,Result,i+1,tmp)------------再次執行combine......

n= 4 k= 2 Result= [] index= 3 tmp= [1, 2]

---len(tmp)==k------------目前 Result= [[1, 2]]

結束 combine 未 pop 前 tmp= [1, 2]

結束 combine 已 pop 後 tmp= [1]

For 迴圈的 i= 3

---tmp.append(i)------------未進入combine前 tmp= [1, 3]

---combine(n,k,Result,i+1,tmp)------------再次執行combine......

n= 4 k= 2 Result= [[1, 2]] index= 4 tmp= [1, 3]

---len(tmp)==k------------目前 Result= [[1, 2], [1, 3]]

結束 combine 未 pop 前 tmp= [1, 3]

結束 combine 已 pop 後 tmp= [1]

For 迴圈的 i= 4

---tmp.append(i)------------未進入combine前 tmp= [1, 4]

---combine(n,k,Result,i+1,tmp)------------再次執行combine......

n= 4 k= 2 Result= [[1, 2], [1, 3]] index= 5 tmp= [1, 4]

---len(tmp)==k------------目前 Result= [[1, 2], [1, 3], [1, 4]]

結束 combine 未 pop 前 tmp= [1, 4]

結束 combine 已 pop 後 tmp= [1]

結束 combine 未 pop 前 tmp= [1]

結束 combine 已 pop 後 tmp= []

For 迴圈的 i= 2

---tmp.append(i)------------未進入combine前 tmp= [2]

---combine(n,k,Result,i+1,tmp)------------再次執行combine......

n= 4 k= 2 Result= [[1, 2], [1, 3], [1, 4]] index= 3 tmp= [2]

進入For 迴圈前 index= 3 n+1= 5

For 迴圈的 i= 3

---tmp.append(i)------------未進入combine前 tmp= [2, 3]

---combine(n,k,Result,i+1,tmp)------------再次執行combine......

n= 4 k= 2 Result= [[1, 2], [1, 3], [1, 4]] index= 4 tmp= [2, 3]

---len(tmp)==k------------目前 Result= [[1, 2], [1, 3], [1, 4], [2, 3]]

結束 combine 未 pop 前 tmp= [2, 3]

結束 combine 已 pop 後 tmp= [2]

For 迴圈的 i= 4

---tmp.append(i)------------未進入combine前 tmp= [2, 4]

---combine(n,k,Result,i+1,tmp)------------再次執行combine......

n= 4 k= 2 Result= [[1, 2], [1, 3], [1, 4], [2, 3]] index= 5 tmp= [2, 4]

---len(tmp)==k------------目前 Result= [[1, 2], [1, 3], [1, 4], [2, 3], [2, 4]]

結束 combine 未 pop 前 tmp= [2, 4]

結束 combine 已 pop 後 tmp= [2]

結束 combine 未 pop 前 tmp= [2]

結束 combine 已 pop 後 tmp= []

For 迴圈的 i= 3

---tmp.append(i)------------未進入combine前 tmp= [3]

---combine(n,k,Result,i+1,tmp)------------再次執行combine......

n= 4 k= 2 Result= [[1, 2], [1, 3], [1, 4], [2, 3], [2, 4]] index= 4 tmp= [3]

進入For 迴圈前 index= 4 n+1= 5

For 迴圈的 i= 4

---tmp.append(i)------------未進入combine前 tmp= [3, 4]

---combine(n,k,Result,i+1,tmp)------------再次執行combine......

n= 4 k= 2 Result= [[1, 2], [1, 3], [1, 4], [2, 3], [2, 4]] index= 5 tmp= [3, 4]

---len(tmp)==k------------目前 Result= [[1, 2], [1, 3], [1, 4], [2, 3], [2, 4], [3, 4]]

結束 combine 未 pop 前 tmp= [3, 4]

結束 combine 已 pop 後 tmp= [3]

結束 combine 未 pop 前 tmp= [3]

結束 combine 已 pop 後 tmp= []

For 迴圈的 i= 4

---tmp.append(i)------------未進入combine前 tmp= [4]

---combine(n,k,Result,i+1,tmp)------------再次執行combine......

n= 4 k= 2 Result= [[1, 2], [1, 3], [1, 4], [2, 3], [2, 4], [3, 4]] index= 5 tmp= [4]

進入For 迴圈前 index= 5 n+1= 5

結束 combine 未 pop 前 tmp= [4]

結束 combine 已 pop 後 tmp= []

FinalResult= [[1, 2], [1, 3], [1, 4], [2, 3], [2, 4], [3, 4]]

LeetCode 78. Subsets

*******************************************

res=[]

def dfs(nums,tmp,i):

res.append(tmp[:])

for i in range(i,len(nums)):

print("i=",i)

tmp.append(nums[i])

print("tmp.append(nums[",i,"])......tmp=",tmp)

dfs(nums,tmp,i+1)

print()

print("i=",i)

print("dfs(nums,tmp,",i+1,")......遞迴前tmp=",tmp)

tmp.pop()

print("i=",i)

print("tmp.pop()......遞迴後tmp=",tmp)

print()

return res

nums=[1,2,3]

dfs(nums,[],0)

print("FinalResult=",res)

=========

i= 0

tmp.append(nums[ 0 ])......tmp= [1]

i= 1

tmp.append(nums[ 1 ])......tmp= [1, 2]

i= 2

tmp.append(nums[ 2 ])......tmp= [1, 2, 3]

i= 2

dfs(nums,tmp, 3 )......遞迴前tmp= [1, 2, 3]

i= 2

tmp.pop()......遞迴後tmp= [1, 2]

i= 1

dfs(nums,tmp, 2 )......遞迴前tmp= [1, 2]

i= 1

tmp.pop()......遞迴後tmp= [1]

i= 2

tmp.append(nums[ 2 ])......tmp= [1, 3]

i= 2

dfs(nums,tmp, 3 )......遞迴前tmp= [1, 3]

i= 2

tmp.pop()......遞迴後tmp= [1]

i= 0

dfs(nums,tmp, 1 )......遞迴前tmp= [1]

i= 0

tmp.pop()......遞迴後tmp= []

i= 1

tmp.append(nums[ 1 ])......tmp= [2]

i= 2

tmp.append(nums[ 2 ])......tmp= [2, 3]

i= 2

dfs(nums,tmp, 3 )......遞迴前tmp= [2, 3]

i= 2

tmp.pop()......遞迴後tmp= [2]

i= 1

dfs(nums,tmp, 2 )......遞迴前tmp= [2]

i= 1

tmp.pop()......遞迴後tmp= []

i= 2

tmp.append(nums[ 2 ])......tmp= [3]

i= 2

dfs(nums,tmp, 3 )......遞迴前tmp= [3]

i= 2

tmp.pop()......遞迴後tmp= []

FinalResult= [[], [1], [1, 2], [1, 2, 3], [1, 3], [2], [2, 3], [3]]

Merge Sort: divide -> conquer -> combine

*******************************************

def divide(Lst):

if len(Lst)>1:

M=(0+len(Lst))//2

Lt=Lst[:M]

Rt=Lst[M:]

divide(Lt)

divide(Rt)

conquer_combine(Lst,Lt,Rt)

return Lst

def conquer_combine(Lst,L,R):

L.append(float("inf"))

R.append(float("inf"))

i=0;j=0

for k in range(len(Lst)):

if L[i]<=R[j]:

Lst[k]=L[i]

i+=1

else:

Lst[k]=R[j]

j+=1

Data=[50,40,30,20]

print(divide(Data))

=========

[20, 30, 40, 50]

Max Subarray Kadane's algorithm

*******************************************

arr=[4,-3,-2,2,3,1,-2,-3,6,-6,-4,2,1]

curr_sum=0

max_so_far=arr[0]

print("剛開始 curr_sum=",curr_sum," max_so_far=",max_so_far)

st=0;en=0;poi=0

for i in range(0,len(arr)):

print("目前項目=",arr[i]," curr_sum=",curr_sum,"+",arr[i])

curr_sum=curr_sum+arr[i]

if(max_so_far<curr_sum):

st=poi;end=i

max_so_far=curr_sum

print("\n因 max_so_far<curr_sum 成立所以 max_so_far=",max_so_far,"\n")

if curr_sum<0:

poi=i+1

curr_sum=0

print("\nFinalResult=",max_so_far)

print("開始項目=",arr[st])

print("結束項目=",arr[end])

=========

剛開始 curr_sum= 0 max_so_far= 4

目前項目= 4 curr_sum= 0 + 4

目前項目= -3 curr_sum= 4 + -3

目前項目= -2 curr_sum= 1 + -2

目前項目= 2 curr_sum= 0 + 2

目前項目= 3 curr_sum= 2 + 3

因 max_so_far<curr_sum 成立所以 max_so_far= 5

目前項目= 1 curr_sum= 5 + 1

因 max_so_far<curr_sum 成立所以 max_so_far= 6

目前項目= -2 curr_sum= 6 + -2

目前項目= -3 curr_sum= 4 + -3

目前項目= 6 curr_sum= 1 + 6

因 max_so_far<curr_sum 成立所以 max_so_far= 7

目前項目= -6 curr_sum= 7 + -6

目前項目= -4 curr_sum= 1 + -4

目前項目= 2 curr_sum= 0 + 2

目前項目= 1 curr_sum= 2 + 1

FinalResult= 7

開始項目= 2

結束項目= 6

Max Subarray BruteForce

*******************************************

def BruteForce(Lst):

n=len(Lst)

tmp=[]

maxsum=float("-inf")

for i in range(n):

for j in range(i+1,n+1):

tmp=Lst[i:j]

print(tmp,"sum=",sum(tmp))

maxsum=max(maxsum,sum(tmp))

print("項目 ",Lst[i]," maxsum=",maxsum,"\n")

#print("Final maxsum=",maxsum)

return maxsum

Data=[-2,-3,4,-1,-2,1,5,-3]

Result=BruteForce(Data)

print("FinalResult=",Result)

=========

[-2] sum= -2

[-2, -3] sum= -5

[-2, -3, 4] sum= -1

[-2, -3, 4, -1] sum= -2

[-2, -3, 4, -1, -2] sum= -4

[-2, -3, 4, -1, -2, 1] sum= -3

[-2, -3, 4, -1, -2, 1, 5] sum= 2

[-2, -3, 4, -1, -2, 1, 5, -3] sum= -1

項目 -2 maxsum= 2

[-3] sum= -3

[-3, 4] sum= 1

[-3, 4, -1] sum= 0

[-3, 4, -1, -2] sum= -2

[-3, 4, -1, -2, 1] sum= -1

[-3, 4, -1, -2, 1, 5] sum= 4

[-3, 4, -1, -2, 1, 5, -3] sum= 1

項目 -3 maxsum= 4

[4] sum= 4

[4, -1] sum= 3

[4, -1, -2] sum= 1

[4, -1, -2, 1] sum= 2

[4, -1, -2, 1, 5] sum= 7

[4, -1, -2, 1, 5, -3] sum= 4

項目 4 maxsum= 7

[-1] sum= -1

[-1, -2] sum= -3

[-1, -2, 1] sum= -2

[-1, -2, 1, 5] sum= 3

[-1, -2, 1, 5, -3] sum= 0

項目 -1 maxsum= 7

[-2] sum= -2

[-2, 1] sum= -1

[-2, 1, 5] sum= 4

[-2, 1, 5, -3] sum= 1

項目 -2 maxsum= 7

[1] sum= 1

[1, 5] sum= 6

[1, 5, -3] sum= 3

項目 1 maxsum= 7

[5] sum= 5

[5, -3] sum= 2

項目 5 maxsum= 7

[-3] sum= -3

項目 -3 maxsum= 7

FinalResult= 7

Max Subarray DynamicProgramming

*******************************************

def DynamicProgramming(Lst):

print("原始Lst=",Lst)

n=len(Lst)

for i in range(1,n):

print("目前項目:",Lst[i])

if Lst[i-1]>0:

print("前一項",Lst[i-1],"因為大於0")

Lst[i]=Lst[i]+Lst[i-1]

print("兩項相加，再寫入後 Lst=",Lst,"\n")

ans=max(Lst)

return ans

Data=[-2,-3,4,-1,-2,1,5,-3]

Res=DynamicProgramming(Data)

print("FinalResult=",Res)

=========

原始Lst= [-2, -3, 4, -1, -2, 1, 5, -3]

目前項目: -3

目前項目: 4

目前項目: -1

前一項 4 因為大於0

兩項相加，再寫入後 Lst= [-2, -3, 4, 3, -2, 1, 5, -3]

目前項目: -2

前一項 3 因為大於0

兩項相加，再寫入後 Lst= [-2, -3, 4, 3, 1, 1, 5, -3]

目前項目: 1

前一項 1 因為大於0

兩項相加，再寫入後 Lst= [-2, -3, 4, 3, 1, 2, 5, -3]

目前項目: 5

前一項 2 因為大於0

兩項相加，再寫入後 Lst= [-2, -3, 4, 3, 1, 2, 7, -3]

目前項目: -3

前一項 7 因為大於0

兩項相加，再寫入後 Lst= [-2, -3, 4, 3, 1, 2, 7, 4]

FinalResult= 7

MergeSort (過程參考此例)

*******************************************

def divide(Lst):

if len(Lst)>1:

M=(0+len(Lst))//2

L=Lst[:M]

R=Lst[M:]

print("divide_L=",L)

print("divide_R=",R)

divide(L)

divide(R)

conquer_combine(Lst,L,R)

return Lst

def conquer_combine(Lst,L,R):

L.append(float("inf"))

R.append(float("inf"))

print("conquer_combine前 L=",L)

print("conquer_combine前 R=",R)

i=0;j=0

for k in range(len(Lst)):

if L[i]<=R[j]:

Lst[k]=L[i]

i+=1

else:

Lst[k]=R[j]

j+=1

print("conquer_combine後 Lst=",Lst,"\n")

Data=[-2,-3,4,-1,-2,1,5,-3]

Res=divide(Data)

print("FinalResult=",Res)

=========

divide_L= [-2, -3, 4, -1]

divide_R= [-2, 1, 5, -3]

divide_L= [-2, -3]

divide_R= [4, -1]

divide_L= [-2]

divide_R= [-3]

conquer_combine前 L= [-2, inf]

conquer_combine前 R= [-3, inf]

conquer_combine後 Lst= [-3, -2]

divide_L= [4]

divide_R= [-1]

conquer_combine前 L= [4, inf]

conquer_combine前 R= [-1, inf]

conquer_combine後 Lst= [-1, 4]

conquer_combine前 L= [-3, -2, inf]

conquer_combine前 R= [-1, 4, inf]

conquer_combine後 Lst= [-3, -2, -1, 4]

divide_L= [-2, 1]

divide_R= [5, -3]

divide_L= [-2]

divide_R= [1]

conquer_combine前 L= [-2, inf]

conquer_combine前 R= [1, inf]

conquer_combine後 Lst= [-2, 1]

divide_L= [5]

divide_R= [-3]

conquer_combine前 L= [5, inf]

conquer_combine前 R= [-3, inf]

conquer_combine後 Lst= [-3, 5]

conquer_combine前 L= [-2, 1, inf]

conquer_combine前 R= [-3, 5, inf]

conquer_combine後 Lst= [-3, -2, 1, 5]

conquer_combine前 L= [-3, -2, -1, 4, inf]

conquer_combine前 R= [-3, -2, 1, 5, inf]

conquer_combine後 Lst= [-3, -3, -2, -2, -1, 1, 4, 5]

FinalResult= [-3, -3, -2, -2, -1, 1, 4, 5]

*******************************************

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2021年7月17日星期六

Python 基本操作

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內容選單標籤

2021年7月17日 星期六

Python 基本操作

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2021年7月17日星期六