python-day10--file Processing

1. File: Is the concept provided by the operating system

2. Open (r+ ' file path ', ' Open with ', ' what character encoding ') #r represent the original string

Eg:open (R ' C:\Users\13264\Desktop\aaaa.py ', ' R ', encoding= ' utf-8 ')

3. File Open:

F=open (R ' aaaa.py ')

This process is equal to two things: the first is the operating system to open the file, the second is to open space in memory a variable

4. File Recycling:

F.close # This is the memory occupied at the shutdown OS level

5. How to handle the file:

① text file: read-only mode, file does not exist error

Read readable ReadLine readlines

Extension: Move the cursor to seek

② text File: Write-only mode, file does not exist will be created, file exists will empty file contents

Write writeable Writelines

③ text file: Append write mode only, ' A ', file does not exist then create, exist then add content at the end of text

④b Mode: bytes mode

#rb
# f=open (' aaaa.py ', ' RB ')
# Print (F.read (). Decode (' Utf-8 '))

# f=open (' 1.jpg ', ' RB ')
# Data=f.read ()

#wb
# f=open (' 2.jpg ', ' WB ')
# f.write (data)


# f=open (' New_3.txt ', ' WB ')
# f.write (' aaaaa\n '. Encode (' Utf-8 '))

#ab
F=open (' new_3.txt ', ' AB ')
F.write (' aaaaa\n '. Encode (' Utf-8 '))

6. Context Management: Don't worry about file close

# with Open (R ' aaaa.py ', ' R ', encoding= ' Utf-8 ') as read_f,\
#         Open (R ' aaaa_new.py ', ' W ', encoding= ' Utf-8 ') as Write_f:
#     Data=read_f.read ()
#     Write_f.write (data)

7. #循环取文件每一行内容

  With open (' A.txt ', ' R ', encoding= ' utf-8 ') as F:
    # while True:
    #     Line=f.readline ()
    #     if not line:break
    #     Print (line,end= ")

    # lines=f.readlines () #只适用于小文件
    # Print (lines)
     For line in F: #推荐使用

         Print (line,end= ")

8. Modification of documents

#方式一: For small files only
# import OS
# with open (' A.txt ', ' R ', encoding= ' Utf-8 ') as read_f,\
#         Open (' A.txt.swap ', ' W ', encoding= ' Utf-8 ') as Write_f:
#     Data=read_f.read ()
#     Write_f.write (data.replace (' alex_sb ', ' ALEX_BSB '))
#
# os.remove (' A.txt ')
# os.rename (' A.txt.swap ', ' a.txt ')


#方式二:
Import OS
With open (' A.txt ', ' R ', encoding= ' Utf-8 ') as read_f,\
        Open (' A.txt.swap ', ' W ', encoding= ' Utf-8 ') as Write_f:
    For line in Read_f:
        Write_f.write (Line.replace (' ALEX_BSB ', ' BB_ALEX_SB '))

Os.remove (' A.txt ')
Os.rename (' A.txt.swap ', ' a.txt ')

python-day10--file Processing