Python notes files

1, File open and create#file () Used for file management (name, mode [, Buffering]]) name is filename, present-open; not present-create mode for open mode, R, R+, W, w+, A, A +, B, u, etc.
2, read the file

#open () reads the file Data=open (' file_name ') #打开一个文件print (Data.redline (), end= ") #用readline () reads a data row Data.seek (0) # Go back to the beginning of the file for the Dataprint (line, end= ") data.close () #关闭文件

How to read a file # #) read by line

f = open ("file.txt") while True:line = F.readline () if Line:print lineelse:break;f.close ()

#2) multi-line Read

f = open (' file.txt ') lines=f.readlines () #readlines () the entire contents of F are saved for the line in the Linesprint line

#3) reads read () once

f = open (' file.txt ') content = F.read () print contentf.close ()

3, File Write

#write (), Writelines () write Files f = file (' file.txt ', ' w+ ') #w + read and write mode open, first delete original, then write new content line = ["Hello \ n", "World \"]f.writelines ( Li) f.close () #追加新内容f = file (' Hello.txt ', ' A + ') content = "Goodbye" f.write (content) F.close ()

4, file Deletion # requires the use of OS module and Os.path Module #os module's open () and file () function and Python built-in usage differs

Import osfile (' Hello.txt ', ' W ') If Os.path.exists (' Hello.txt ') os.remove (' Hello.txt ')

5, File copy

#用read () and write () implementation copy src = file ("Hello.txt", "r") DST = File ("Hello2.txt", "W") Dst.write (Src.read ()) Src.close () Dst.close () #shutil模块 copyfile () function #copyfile (src, DST) # File copy shutil.copyfile ("Hello.txt", "Hello2.txt") #move (SRC, DST) #文件剪切, Move shutil.move ("Hello.txt", "... /") #移动到父目录下shutil. Move (" Hello2.txt "," Hello3.txt ") #移动 + rename

6, File Rename

The rename () function of the #修改文件名 OS module import osos.rename ("Hello.txt", "Hi.txt") #修改后缀名import osfiles = Os.listdir (".") for filename in files:pos = Filename.find (".") If filename[pos+1:] = = "html": newname = filename[:p os+1] + "JSP" os.rename (filename, newname)

7, File content search

#文件查找import ref1 = File ("Hello.txt", "r") Count = 0for s in f1.readlines (): Li = Re.findall ("Hello", s) #findall () query variable s, find results Save to Li If Len (li) > 0:count = Count + li.count ("Hello") print count, "Hello" f1.close () #文件替换f1 = File ("Hello.txt", "R") F2 = File ("Hello2.txt", "W") for S in F1.readlines (): F2.write (S.replace ("Hello", "HI")) f1.close () F2.close ()

8, file comparison #difflib module for sequence, file comparison
9, configuration file access #python standard library Configparser module term resolution profile
10, files and streams

#sys模块中提供了stdin, stdout,stderr three basic Stream object Import Sys#stdin represents the standard input of the stream Sys.stdin = open ("Hello.txt", "R") #读取文件for line in Sys.stdin.readlines () print line#stdout redirect output, save output to file Sys.stdout = open (r "./hello.txt", "a") print "Goodbye" Sys.stdout.close ()

Python notes files