Python development "Article xxx" file operation----Review

1: #r模式, a new file is not created when the file does not exist

f = open (' A.txt ', ' r ', encoding = ' utf-8 ')

2: Character encoding

What is character encoding?

Translate human characters into numbers that computers can recognize

What is a character encoding table?

Ascii

GBK

UTF-8

Unicode

Unicode-------->encode (' utf-8 ')-------------->bytes

Bytes------------>decode (' utf-8 ')--------------->unicode

Principle:

What format the character is compiled in and what format it will decode

Ps:

The characters in Python3 are divided into two types

x= ' Egon ' into Unicode

Y=x.encode (' Utf-8 ') saved into bytes

The strings in Python2 are also divided into two types

x = U ' Egon ' is the same as the string in Python3

Y= ' Alex ' is the same as the bytes type in Python3

 #r模式的读, does not create a new file when the file does not exist 
 F = open (' A.txt ', ' r ', encoding = ' utf-8 ') 
 Print (F.read ()) 
 F.close () 
 
 
 #b模式即直接从硬盘中读取bytes 
 Print (F.read () decode (' Utf-8 ') 
 
 #w文本模式的写, file exists is empty, does not exist create 
 F = open (' A.txt ', ' W ') , encoding = ' utf-8 ') 
 F = open (' B.txt ', ' w ', encoding = ' utf-8 ') 
 Print (f.writeable ()) #判断是否可写 
 Print (f.readable ( ) #判断是否可读 
 
 #a文本模式的追加 
 F = open (' B.txt ', ' a ', encoding = ' utf-8 ') 
 Print (f.writeable ()) #写文件涉及到文件光标的移动 
 Print (F.tell ()) 
 Print (F.readline ()) 
 F.write (' 333\n ') 
 #r +,w+,a+, can be written when read, can be read when writing 
 
 # RB mode reads directly from the hard drive bytes 
 F = open (' a.txt ', ' RB ') 
 Print (F.read (). Decode (' Utf-8 ')) 
 
 #wb模式 
 F = open (' A.txt ', ' WB ') 
 F.write (' Hello '. Encode (' Utf-8 ') 
 
 
 # #b模式可以读取任何模式的文件 
 with open (' test.jpg ', ' RB ') as Read_f,\ 
 O Pen (' test1.jpg ', ' WB ') as Write_f: 
 for line in Read_f: 
 Write_f.write (line) 
 
 ####### ###################################################

f = open (' A.txt ', ' r ', encoding = ' utf-8 ')
Print (F.read ())
#f. Read () can specify multiple, read as text, in characters

f = open (' a.txt ', ' RB ')
Print (F.read (3). Decode (' Utf-8 '))
#以字节为单位, 1 Chinese accounts for 3 bytes, in text mode, read in characters, in B mode, in bytes, the rest of the files within the cursor movement are in bytes


f = open (' A.txt ', ' r ', encoding = ' utf-8 ')
Print (F.read ())
F.seek (0) #表示将光标的位置移动到开头
Print (F.read ())
F.seek (1) #表示从第一个字符开始读取
Print (F.tell ()) #tell表示以字节显示的

F.seek (6,0) #代表从文件开头取6个字节, according to the read mode, if it is readable mode, the character is read, the other reads the byte
F.seek (6,1) #以当前光标所在的位置为参照物
#seek有3种移动方式0, 1 and 2 must be in B mode, and 0 can be used in text mode

f = open (' a.txt ', ' RB ')
F.seek (0,2) #此时光标一直指向最后
F.seek ( -1,2) #倒着切一个字节


CP text

1 ## # #文件习题2 Import Time3With open ('Test.txt','RB') as F:4 f.seek (0)5      whileTrue:6line =F.readline ()7         ifLine :8             Print(Line.decode ('Utf-8'), end="')9         Else:TenTime.sleep (0.5)

Python development "Article xxx" file operation----Review