[python]基本文件操作

　　1. file_object = open(file_name, access_mode='r', buffering=-1)

关于acess_mode的解释

File Mode 　　　　　　Operation

r 　　　　　　　　　　Open for read

rU or U　　　　　　　 Open for read with universal NEWLINE support (PEP 278)

w 　　　　　　　　　  Open for write (truncate if necessary)

a 　　　　　　　　　  Open for append (always works from EOF, create if necessary)

r+　　　　　　　　    Open for read and write

w+ 　　　　　　　　  Open for read and write (see w above)

a+ 　　　　　　　　　Open for read and write (see a above)

rb 　　　　　　　　　 Open for binary read

wb 　　　　　　　　　Open for binary write (see w above)

ab 　　　　　　　　   Open for binary append (see a above)

rb+ 　　　　       　　Open for binary read and write (see r+ above)

wb+　　　　　　　　 Open for binary read and write (see w+ above)

ab+　　　　　　　　  Open for binary read and write (see a+ above)

+ is for  read-write access

 

2.  任何使用open()的地方都可以使用file()代替

Generally, the accepted style is that you use open() for reading/writing files, while file() is 

best used when you want to show that you are dealing with file objects, i.e., if instance(f, file).

 

3. seek(pos, whence=0) 没有返回值

seek() moves the file pointer to different positions within the file.The offset in bytes is given

along with a relative offset location, whence. A value of 0, the default, indicates distance from

the beginning of a file (note that a position measured from the beginning of a file is also known

as the absolute offset), a value of 1 indicates movement from the current location in the file,

and a value of 2 indicates that the offset is from the end of the file.

tell()可以返回目前所在的位置 特可以配合seek()使用

 

4.

OS Module Attributes to Aid in Multi-platform Development

Attribute 　　　　　　　　Description

linesep 　　　　　　　　   String used to separate lines in a file

sep 　　　　　　　　　　  String used to separate file pathname components

pathsep　　　　　　　　  String used to delimit a set of file pathnames

curdir 　　　　　　　　　 String name for current working directory

pardir　　　　　　　　　  String name for parent (of current working directory)

 

5. 除了file, os和os.path提供了一系列操作文件目录的方法。