Python file io (normal file read/write)

# # Open a file
-fileobj = open (filename, mode)
which
Fileobj is the file object returned by open ()
FileName is the string name of the file
Mode is a substring that indicates the file type and operation
　　
-the first letter of mode indicates its operation
-R indicates read
-W indicates write, if the file does not exist, it is created, if present, re-writes the new content
-X means to create and write a file without a file present
-A indicates that if the file exists, append the content to the end of the file

-The second letter of mode is the file type
-T (or omit) represents the text type
-B stands for binary files

# # Write file using write (), close file with close ()

1Poem ="""2 from the original grass, one year old a withered flourish. 3 The wild Fire is endless, the spring breeze blows and is born. 4 Far Fang invaded the ancient road, clear Cui Connect desolate city. 5 send Monarch again, luxuriant full sharpens. 6 """7File_obj = open ("Poems",'WT')#open a text file named ' poem ' and create a ' poem ' If it does not exist8File_obj.write (poem)#Write File9File_obj.close ()#Close File

-You can also write files using print ()

1Poem ="""2 from the original grass, one year old a withered flourish. 3 The wild Fire is endless, the spring breeze blows and is born. 4 Far Fang invaded the ancient road, clear Cui Connect desolate city. 5 send Monarch again, luxuriant full sharpens. 6 """7File_obj = open ("Poems",'WT')#open a text file named ' poem ' and create a ' poem ' If it does not exist8 Print(Poem, file=file_obj)#Write File9File_obj.close ()#Close File

-If you need to write a lot of content, you can write data chunked

1Poem ="""2 from the original grass, one year old a withered flourish. 3 The wild Fire is endless, the spring breeze blows and is born. 4 Far Fang invaded the ancient road, clear Cui Connect desolate city. 5 send Monarch again, luxuriant full sharpens. 6 """7File_obj = open ("Poems",'WT')#open a text file named ' poem ' and create a ' poem ' If it does not exist8 9Start =0TenChunk = 20#write 20 characters at a time One  whileTrue: A     ifStart >Len (poem): -          Break -File_obj.write (poem[start:start+Chunk]) theStart + =Chunk -  -File_obj.close ()#Close File

# # File Read
-Read (): Read () function without parameters reads all the contents of the file at one time

1File_obj = open ("Poems",'RT')#To open a text file using read mode2Poem = File_obj.read ()#Read all the contents of a file3File_obj.close ()#Close File4 Print(poem)5 """6 Output:7 from the original grass, one year old a withered flourish. 8 The wild Fire is endless, the spring breeze blows and is born. 9 Far Fang invaded the ancient road, clear Cui Connect desolate city. Ten send Monarch again, luxuriant full sharpens.  One """

　

-can also be read in chunks

1Poem ="'2File_onj = open ("Poems",'RT')3Chunk = 20#reads 20 characters at a time4  whileTrue:5Frag =File_onj.read (Chunk)6     if  notFrag#calling the Read () function again at the end of the file returns an empty string, not frag true, and execution break7          Break8Poem + =Frag9 Ten Print(poem) One """ A Output: - from the original grass, one year old a withered flourish.  - The wild Fire is endless, the spring breeze blows and is born.  the Far Fang invaded the ancient road, clear Cui Connect desolate city.  - send Monarch again, luxuriant full sharpens.  - """

-A row of reads

1Poem ="'2File_obj = open ('Poems','RT')3  whileTrue:4line =File_obj.readline ()5     if  notLine :6          Break7Poem + = Line8 9 Print(poem)Ten """ One Output: A from the original grass, one year old a withered flourish.  - The wild Fire is endless, the spring breeze blows and is born.  - Far Fang invaded the ancient road, clear Cui Connect desolate city.  the send Monarch again, luxuriant full sharpens.  - """

-use iterators to read files

1Poem ="'2File_obj = open ("Poems",'RT')3  forLineinchFile_obj:#same effect, but shorter code4Poem + = Line5 6 Print(poem)7 """8 Output:9 from the original grass, one year old a withered flourish. Ten The wild Fire is endless, the spring breeze blows and is born.  One Far Fang invaded the ancient road, clear Cui Connect desolate city.  A send Monarch again, luxuriant full sharpens.  - """

-ReadLines (): reads one line at a time and returns a list of single-line strings

1File_obj = open ("Poems",'RT')2Lines =File_obj.readlines ()3 Print(lines)4  forLineinchlines:5     Print(Line, end="')6     7 """8 [' \ n ', ' the grass from the original, one year old and one withered flourish. \ n ', ' The wild Fire is endless, the spring breeze blows and is born. \ n ', ' The Far Fang invaded the ancient road, the fine Cui connect the desolate city. \ n ', ' send monarch again, luxuriant full sharpens. \ n ']9 Ten from the original grass, one year old a withered flourish.  One The wild Fire is endless, the spring breeze blows and is born.  A Far Fang invaded the ancient road, clear Cui Connect desolate city.  - send Monarch again, luxuriant full sharpens.  - """

# # Write () writes a binary file

1 # converting a sequence to binary data 2 f = open ('bin_file'wb')      #  Open file in binary format 3 f.write (bin_data)               #  write 4 f.close ()                       # Close

-Segmented Write

1Bin_data = bytes (range (0, 255))2f = open ('Bin_file','WB')3Chunk = 100#write 100 bytes at a time4offset =05  whileTrue:6     ifOffset >Len (bin_date):7          Break8F.write (Bin_data[offset:chunk +offset])9Offset + =ChunkTen  OneF.close ()

-Read binary files

1 f = open ('bin_file'rb')2 bin_ data = F.read ()3 f.close ()

# # Use with auto close file, auto close file after complete with code block

1With open ("Poems",'RT') as F:2Poem =F.read ()3 4 Print(poem)5 """6 Output:7 from the original grass, one year old a withered flourish. 8 The wild Fire is endless, the spring breeze blows and is born. 9 Far Fang invaded the ancient road, clear Cui Connect desolate city. Ten send Monarch again, luxuriant full sharpens.  One """

This article refers to:

Beauty Bill Lubanovic "Python language and its application"

Python file io (normal file read/write)