Copy Coding

모드

의미

r

읽기 – 파일을 읽기 위해 오픈 (default). 파일 없으면 오류

w

쓰기 – 파일을 쓰기모드로 오픈. 파일 없으면 생성, 있으면 삭제 생성

x

open for exclusive creation, failing if the file already exists

a

쓰기 – 끝에 추가, 없으면 생성

b

이진 모드

t

텍스트 모드 (default)

+

업데이트용 파일 오픈 (읽기, 쓰기 가능)

 r+

 w+

 a+

sum = 0

f = open("F:/Python/file_write01.txt", 'w')

for i in range(1,101):

           sum += i

           tmp_data = "sum( %d ) = %d + %d\n"  % (sum , sum, i)

           f.write(tmp_data)

print(sum)

f.close()

(base) F:\Python>python file_w01.py

5050

sum( 1 ) = 1 + 1

sum( 3 ) = 3 + 2

sum( 6 ) = 6 + 3

sum( 10 ) = 10 + 4

sum( 15 ) = 15 + 5

sum( 21 ) = 21 + 6

sum( 28 ) = 28 + 7

sum( 36 ) = 36 + 8

sum( 45 ) = 45 + 9

....(생략)

list_data = ['aaaa', 'bbbb','cccc']

f = open("F:/Python/file_write02.txt", 'w')

f.write('\n'.join(list_data))

f.close()

(base) F:\Python>python file_w02.py

aaaa

bbbb

cccc

list_data = ['aaaa', 'bbbb','cccc']

f = open("F:/Python/file_write03.txt", 'w')

f.writelines(list_data)

f.close()

(base) F:\Python>python file_w03.py

aaaabbbbcccc

try:

   f = open("F:/Python/file_write01.txt", 'r')

   data = f.read()

   print(data)

except FileNotFoundError as e:

           print(e)

finally:

   f.close()

전체 읽기

(base) F:\Python>python file_r01.py

sum( 1 ) = 1 + 1

sum( 3 ) = 3 + 2

sum( 6 ) = 6 + 3

sum( 10 ) = 10 + 4

sum( 15 ) = 15 + 5

sum( 21 ) = 21 + 6

...(생략)

try:

   f = open("F:/Python/file_write01.txt", 'r')

   data = f.read(100)

   print(data)

except FileNotFoundError as e:

           print(e)

finally:

   f.close()

100 byte 읽기

(base) F:\Python>python file_r02.py

sum( 1 ) = 1 + 1

sum( 3 ) = 3 + 2

sum( 6 ) = 6 + 3

sum( 10 ) = 10 + 4

sum( 15 ) = 15 + 5

sum( 21 ) =

try:

   f = open("F:/Python/file_write01.txt", 'r')

   data = f.readline()

   print(data)

except FileNotFoundError as e:

           print(e)

finally:

   f.close()

한라인만 읽어와 출력 합니다.

(base) F:\Python>python file_r03.py

sum( 1 ) = 1 + 1

try:

   f = open("F:/Python/file_write01.txt", 'r')

   data_list = f.readlines()

   data_length = len(data_list)

   print("list count : " + str(data_length))

   print(data_list[0])

   print(data_list)

except FileNotFoundError as e:

           print(e)

finally:

   f.close()

파일의 라인 수와 List의 첫 번째 요소, 전체 출력

(base) F:\Python>python file_r04.py

list count : 100

sum( 1 ) = 1 + 1

['sum( 1 ) = 1 + 1\n', 'sum( 3 ) = 3 + 2\n', 'sum( 6 ) = 6 + 3\n', ...(생략)...]

try:

   이런 저런 명령어 처리

except:

   print(“알 수 없는 오류로 인하여 프로그램이 종료 되었습니다.”)

try:

 fd = open(“filename.txt”, ‘r’)

   line = fd.readline()

except FileNotFoundError:

   print(“요청하신 파일을 찾을 수 없습니다.”)

try:

 fd = open(“filename.txt”, ‘r’)

   line = fd.readline()

except OSError:

   print(“OS 오류가 발생 했습니다.”)

except FileNotFoundError:

   print(“요청하신 파일을 찾을 수 없습니다.”)

except:

 print(“알 수 없는 오류가 발생 했습니다.”)

try:

 fd = open(“filename.txt”, ‘r’)

   line = fd.readline()

except OSError:

   print(“OS 오류가 발생 했습니다.”)

except FileNotFoundError:

   print(“요청하신 파일을 찾을 수 없습니다.”)

except:

 print(“알 수 없는 오류가 발생 했습니다.”)

else:

   print(“오류가 발생하지 않았습니다.”)

try:

 fd = open(“filename.txt”, ‘r’)

   line = fd.readline()

except OSError:

   print(“OS 오류가 발생 했습니다.”)

except FileNotFoundError:

   pass

try:

 fd = open(“filename.txt”, ‘r’)

   line = fd.readline()

except OSError as oe:

   print(oe)

except FileNotFoundError as e:

   print(e)

try:

 fd = open(“filename.txt”, ‘r’)

   line = fd.readline()

finally:

   fd.close()

a = 100

if a <= 150:

           try:

                     raise ValueError

                     b = 2500 / a

           except ZeroDivisionError:

                     print("zero div")

           except ValueError:

                     print("number small")

결과

(base) F:\Python>python except001.py

number small

class UserError(Exception):

           def __init__(self, value):

                     self.value = value

           def __str__(self):

                     return self.value

# 신규 예외사항 사용

a = 100

if a <= 150:

           try:

                     raise UserError("Number error")

                     b = 2500 / a

           except ZeroDivisionError:

                     print("zero div")

결과

(base) F:\Python>python except002.py

Traceback (most recent call last):

  File "except002.py", line 12, in <module>

    raise UserError("Number error")

__main__.UserError: Number error

with open(“filename.txt”) as fd:

    for line in fd:

        print(line, end="")

BaseException

 +-- SystemExit

 +-- KeyboardInterrupt

 +-- GeneratorExit

 +-- Exception

      +-- StopIteration

      +-- StopAsyncIteration

      +-- ArithmeticError

      |    +-- FloatingPointError

      |    +-- OverflowError

      |    +-- ZeroDivisionError

      +-- AssertionError

      +-- AttributeError

      +-- BufferError

      +-- EOFError

      +-- ImportError

      |    +-- ModuleNotFoundError

      +-- LookupError

      |    +-- IndexError

      |    +-- KeyError

      +-- MemoryError

      +-- NameError

      |    +-- UnboundLocalError

      +-- OSError

      |    +-- BlockingIOError

      |    +-- ChildProcessError

      |    +-- ConnectionError

      |    |    +-- BrokenPipeError

      |    |    +-- ConnectionAbortedError

      |    |    +-- ConnectionRefusedError

      |    |    +-- ConnectionResetError

      |    +-- FileExistsError

      |    +-- FileNotFoundError

      |    +-- InterruptedError

      |    +-- IsADirectoryError

      |    +-- NotADirectoryError

      |    +-- PermissionError

      |    +-- ProcessLookupError

      |    +-- TimeoutError

      +-- ReferenceError

      +-- RuntimeError

      |    +-- NotImplementedError

      |    +-- RecursionError

      +-- SyntaxError

      |    +-- IndentationError

      |         +-- TabError

      +-- SystemError

      +-- TypeError

      +-- ValueError

      |    +-- UnicodeError

      |         +-- UnicodeDecodeError

      |         +-- UnicodeEncodeError

      |         +-- UnicodeTranslateError

      +-- Warning

           +-- DeprecationWarning

           +-- PendingDeprecationWarning

           +-- RuntimeWarning

           +-- SyntaxWarning

           +-- UserWarning

           +-- FutureWarning

           +-- ImportWarning

           +-- UnicodeWarning

           +-- BytesWarning

           +-- ResourceWarning

>>> abs(3)

3

>>> abs(-3)

3

>>> abs(0.0002)

0.0002

>>> abs(-0.0002)

0.0002

>>> all([1,2,3])

True

>>> all([4,5,1,3])

True

>>> all([4,5,1,0,3])

False

>>> all(('a', 'b', 'c'))

True

>>> all(('a', 'b', 'c', ''))

False

>>> any([4,5,1,0,3])

True

>>> any(('', 0))

False

# 10 진수

>>> chr(112)

'p'

>>> chr(80)

'P'

# 16 진수

>>> chr(0x50)

'P'

>>> chr(0x70)

'p'

>>> dir(1)

['__abs__', '__add__', '__and__', '__bool__', '__ceil__', '__class__', '__delattr__', '__dir__', '__divmod__', '__doc__', '__eq__', '__float__', '__floor__', '__floordiv__', '__format__', '__ge__', '__getattribute__', '__getnewargs__', '__gt__', '__hash__', '__index__', '__init__', '__init_subclass__', '__int__', '__invert__', '__le__', '__lshift__', '__lt__', '__mod__', '__mul__', '__ne__', '__neg__', '__new__', '__or__', '__pos__', '__pow__', '__radd__', '__rand__', '__rdivmod__', '__reduce__', '__reduce_ex__', '__repr__', '__rfloordiv__', '__rlshift__', '__rmod__', '__rmul__', '__ror__', '__round__', '__rpow__', '__rrshift__', '__rshift__', '__rsub__', '__rtruediv__', '__rxor__', '__setattr__', '__sizeof__', '__str__', '__sub__', '__subclasshook__', '__truediv__', '__trunc__', '__xor__', 'bit_length', 'conjugate', 'denominator', 'from_bytes', 'imag', 'numerator', 'real', 'to_bytes']

>>> dir('a')

['__add__', '__class__', '__contains__', '__delattr__', '__dir__', '__doc__', '__eq__', '__format__', '__ge__', '__getattribute__', '__getitem__', '__getnewargs__', '__gt__', '__hash__', '__init__', '__init_subclass__', '__iter__', '__le__', '__len__', '__lt__', '__mod__', '__mul__', '__ne__', '__new__', '__reduce__', '__reduce_ex__', '__repr__', '__rmod__', '__rmul__', '__setattr__', '__sizeof__', '__str__', '__subclasshook__', 'capitalize', 'casefold', 'center', 'count', 'encode', 'endswith', 'expandtabs', 'find', 'format', 'format_map', 'index', 'isalnum', 'isalpha', 'isdecimal', 'isdigit', 'isidentifier', 'islower', 'isnumeric', 'isprintable', 'isspace', 'istitle', 'isupper', 'join', 'ljust', 'lower', 'lstrip', 'maketrans', 'partition', 'replace', 'rfind', 'rindex', 'rjust', 'rpartition', 'rsplit', 'rstrip', 'split', 'splitlines', 'startswith', 'strip', 'swapcase', 'title', 'translate', 'upper', 'zfill']

>>> divmod(20, 3)

(6, 2)

>>> a = [1, 2, 3, 4, 5]

>>> for i, n in enumerate(a):

...   print(i, n)

...

0 1

1 2

2 3

3 4

4 5

# 오류 발생

>>> eval('a' + 'b')

Traceback (most recent call last):

  File "<stdin>", line 1, in <module>

  File "<string>", line 1, in <module>

NameError: name 'ab' is not defined

# 정상 작동

>>> ab = 555

>>> eval('a' + 'b')

555

>>> def is_even(x):

...    if x % 2 == 0:

...       return True

...    else:

...       return False

...

>>> r = filter(is_even, [1,2, 3, 4, 5, 6,7])

>>> 

>>> for i in r:

...    print(i)

...

2

4

6

>>> r2 = list(filter(lambda x : x % 2 == 0,[1,2, 3, 4, 5, 6,7]))

>>> r2

[2, 4, 6]

>>> hex(5)

'0x5'

>>> hex(10)

'0xa'

>>> hex(15)

'0xf'

>>> a = 'a'

>>> b = a

>>> id(a)

2998919036464

>>> id('a')

2998919036464

>>> id(b)

2998919036464

# a 값 변경

>>> a = 'b'

>>> id(a)

2998919034784

>>> id(b)

2998919036464

>>> x = input()

Y

>>> x = input("계속 진행 하시겠습니까?(Y/N) :")

계속 진행 하시겠습니까?(Y/N) :Y

>>> x

'Y'

>>> int('30')

30

>>> int('-45')

-45

>>> int(3.5444)

3

>>> int(-4.99999)

-4

>>> int('8.9999')

Traceback (most recent call last):

  File "<stdin>", line 1, in <module>

ValueError: invalid literal for int() with base 10: '8.9999'

# 2진수 -> 10진수

>>> int('011', 2)

3

# 16진수 -> 10진수

>>> int('0xA', 16)

10

# 정수가 정수냐?

>>> isinstance(3, int)

True

# 실수가 정수냐?

>>> isinstance(3.0, int)

False

# 실수가 정수 또는 실수냐?

>>> isinstance(3.0, (int, float))

True

# 클래스가 클래스냐?

>>> class OneClass:

...    a = 'aaa'

...

>>> b = OneClass()

>>> c = isinstance(b, OneClass)

>>> c

True

>>> len('abcdefg')

7

>>> len([1, 2, 3, 4])

4

>>> len(['a', 'b', 'cc'])

3

>>> len((1, 2, 3, 4, 5))

5

>>> len(123)

Traceback (most recent call last):

  File "<stdin>", line 1, in <module>

TypeError: object of type 'int' has no len()

>>> list('abcdefg')

['a', 'b', 'c', 'd', 'e', 'f', 'g']

>>> list([1,2,3,4,5])

[1, 2, 3, 4, 5]

>>> list((1,2,3,4,5))

[1, 2, 3, 4, 5]

>>> 

>>> def addFunc(n):

...    return n + n

...

>>> nums = (1, 2, 3, 4, 5)

>>> res = map(addFunc, nums)

>>> print(list(res))

[2, 4, 6, 8, 10]

>>> nums = (1, 2, 3, 4, 5)

>>> result = map(lambda x: x + x, nums)

>>> print(list(result))

[2, 4, 6, 8, 10]

>>> max("PYTHON python")

'y'

>>> max([1, 2, 3, 4.5])

4.5

>>> min("PYTHON python")

' '

>>> min([1, 2, 3, 4.5])

1

>>> oct(8)

'0o10'

>>> oct(10)

'0o12'

f = open(“test_file”, “r”)

>>> ord('a')

97

>>> ord('A')

65

>>> pow(2, 3)

8

>>> pow(3, 3)

27

>>> range(10)

range(0, 10)

>>> list(range(10))

[0, 1, 2, 3, 4, 5, 6, 7, 8, 9]

>>> range(5, 10)

range(5, 10)

>>> list(range(5, 10))

[5, 6, 7, 8, 9]

. >>> range(5, 10, 2)

range(5, 10, 2)

>>> list(range(5, 10, 2))

[5, 7, 9]

>>> round(3.5)

4

>>> round(4)

4

>>> round(4.55555, 3)

4.556

>>> sorted("python")

['h', 'n', 'o', 'p', 't', 'y']

>>> sorted(['a', 'd', 'b', 'k', 'c'])

['a', 'b', 'c', 'd', 'k']

>>> sorted([5,7,2,4,6,8])

[2, 4, 5, 6, 7, 8]

>>> sorted([5,7,2,4,6,8,2])

[2, 2, 4, 5, 6, 7, 8]

>>> sorted((5,7,2,4,6,8,2))

[2, 2, 4, 5, 6, 7, 8]

>>> str(123)

'123'

>>> str(345) + "abc"

'345abc'

>>> str("python".upper())

'PYTHON'

>>> sum((1, 2, 3))

6

>>> sum([1, 2, 3])

6

>>> tuple("python")

('p', 'y', 't', 'h', 'o', 'n')

>>> tuple([1, 2, 3])

(1, 2, 3)

>>> tuple(('a', 'b', 'c'))

('a', 'b', 'c')

>>> type('a')

<class 'str'>

>>> type(1)

<class 'int'>

>>> type([])

<class 'list'>

>>> a = [1, 2, 3, 4, 5]

>>> b = ['a', 'b', 'c', 'd', 'e']

>>> for i in zip(a, b):

...    print(i)

...

(1, 'a')

(2, 'b')

(3, 'c')

(4, 'd')

(5, 'e')

>>> list(zip(a, b))

[(1, 'a'), (2, 'b'), (3, 'c'), (4, 'd'), (5, 'e')]

>>> a = [1, 2, 3, 4, 5]

>>> b = ['a', 'b', 'c', 'd']

>>> list(zip(a, b))

[(1, 'a'), (2, 'b'), (3, 'c'), (4, 'd')]