Python Basic 10-I/O programming

Tag: Buffer file copy src file operation off Stat Ali

I. INPUT and OUTPUT

① input: Input ()

② output: Print ()

1 name=input (' Please enter name ')2print(name)

Second, the file operation

① Open File: File object =open (file name, access mode, buffering)

FileName: Specifies the file to be opened, usually including a path, either an absolute or a relative path

Buffering: Optional parameters, specify the buffer mode used by the file, buffering=0, do not buffer; buffering=1, buffer one line; buffering>1, use the given value as the buffer size

Access mode: Used to specify the mode of open file, the parameter table of access mode is as follows

desirable value
r	read-open
w< /td>	opens in a written manner, when the contents of the file are emptied before the file is created
a
r+ , w+	Open in read-write mode
a+	append read-write mode opens
RB	Open in binary read mode
WB	open in binary write mode
rb+, wb+, ab+	open in binary read-write mode

② Close file: File object. Close ()

③ Read file:

Ⅰ:str= file object. read ([b])

Optional parameter [b]: Specify the number of bytes read, default Read all

The ⅱ:list= file object. ReadLines () reads the contents back into the list of strings

The ⅲ:str= file object. ReadLine () reads all rows from a file at once

Ⅳ: Using the IN keyword: for lines in file object: processing row data line

1F=open ('Test.txt')2Mystr=F.read ()3 f.close ()4 Print(MYSTR)5 6F=open ('Test.txt')7  whileTrue:8Chunk=f.read (10)9     if  notChunk:Ten          Break One     Print(Chunk) AF.close

1F=open ('Test.txt')2mylist=F.readlines ()3 Print(mylist)4 f.close ()5F=open ('Test.txt')6  whileTrue:7chunk=F.readline ()8     if  notChunk:9          BreakTen     Print(Chunk) OneF.close ()

Third, write the file

①write (): File object. write (write content)

② Append write: When opening a file, you can call open () with a or a + as a parameter and then write

③writelines (): File object. (seq) for writing string sequences, seq is a sequence of returned strings (lists, tuples, collections, etc.)

1F=open ('Test.txt','A +')2F.write ('Hello')3 f.close ()4F=open ('Test.txt')5  forLineinchF:6     Print(line)7F.close ()

1mylist=['Hello, Jack .','Hello Salar','Hello Coffee']2F=open ('Test.txt','A +')3 f.writelines (mylist)4 f.close ()5F=open ('Test.txt')6  forLineinchF:7     Print(line)8F.close ()

Iv. File Pointers

① get the file pointer location: pos= file object. Tell () returns an integer that represents the location of the file pointer, the position of the file pointer when a file is opened, 0, and a read-write file where the position of the file pointer moves to the read-write location

② Moving File Pointers: file objects. Seek ((Offset,where))

Offset: The shift in bytes, a positive number moves toward the end of the file, and a negative amount moves toward the head of the file

Where: Refers to where to start moving, 0 is the starting position, equal to 1 o'clock moves for the current position, equal to 2 o'clock starting from the end position to move

1 f=open ('test.txt')2print(F.tell ()) 3 f.close () 4 f=open ('test.txt')5 f.seek (5, 0) 6 Print (F.tell ()) 7 F.close ()

V. Truncation of files

File object. truncate ([size]) truncates the file from the beginning of the file, size is an optional parameter, and the contents of the file after the size byte are truncated and discarded

1F=open ('Test.txt','A +')2F.truncate (5)3 f.close ()4F=open ('Test.txt')5  forLineinchF:6     Print(line)7F.close ()

Vi. Other operations

① file properties: Use the stat () function of the OS module to get the properties of a file, create a time, modify time, access time, file size, and other attributes (to import a module before using: Imported OS)

② Copying files: Using the copy () function of the Shutil module, the function prototype is: Copy (SRC,DST) to copy the source file src to DST

③ moving files: Using the Move () function of the Shutil module, the function prototype is: Move (SRC,DST)

④ renaming files: Using the rename () function of the OS module, the function prototype is: Os.rename (original filename, new file name)

⑤ deleting files: Using the Remove () function of the OS module, the function prototype is: Os.remove (SRC)

1 ImportOS2 ImportShutil3Filestats=os.stat ('Test.txt')4 Print(filestats)5 6Shutil.copy ('F:\\python\\book\\ch7\\test.txt','F:\\python\\book\\ch7\\test2.txt')7Shutil.move ('F:\\python\\book\\ch7\\test2.txt','F:\\python\\book\\test2.txt')8Os.rename ('F:\\python\\book\\test2.txt','F:\\python\\book\\test3.txt')9Os.remove ('F:\\python\\book\\test3.txt')

Seven, directory programming

① get current directory: OS module's GETCWD () function

② Get directory Contents: OS module's Listdir () function

③ Creating a directory: the mkdir () function of the OS module

④ Delete directory: the RmDir () function of the OS module

1 Import OS 2 Print (OS.GETCWD ()) 3 Print (Os.listdir (OS.GETCWD ())) 4 os.mkdir ('f:\\python\\book\ch7\\he')5 Os.rmdir ('f:\\python\\book\ch7\\he')

Python Basic 10-I/O programming