[Python] Python open read/write files

1. Open

After opening a file using open, remember to call the close () method of the file object. For example, you can use the try/finally statement to ensure that the file can be closed at last.
File_object = open('thefile.txt ')
Try:
All_the_text = file_object.read (
)
Finally:
File_object.close ()

Note: The open statement cannot be placed in the try block, because when an exception occurs when the file is opened, the file object file_object cannot execute the close () method.

2. Read the text file input = open ('data', 'R ')
# The second parameter defaults to R.
Input = open ('data ')

Read Binary file input = open ('data', 'rb ')

Read all content file_object = open('thefile.txt ')
Try:
All_the_text = file_object.read (
)
Finally:
File_object.close ()

Read the fixed byte file_object = open ('abinfile', 'rb ')
Try:
While true:
Chunk = file_object.read (100)
If not Chunk:
Break
Do_something_with (chunk)
Finally:
File_object.close ()

Read the list_of_all_the_lines = file_object.readlines (
)

If the file is a text file, you can directly traverse the file object to get each line:
For line in file_object:
Process Line

3. Write a file to write a text file output = open ('data', 'w ')

Write binary file output = open ('data', 'wb ')

Append Write File output = open ('data', 'W + ')

Write Data file_object = open('thefile.txt ', 'w ')
File_object.write (all_the_text)
File_object.close ()

Write multiple lines of file_object.writelines (list_of_text_strings)

Note that calling writelines to write multiple rows has a higher performance than using write for one-time writing.



~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ~~~~~~

The Ru or UA is opened in Read mode and supports common line breaks (PEP 278)
W    Open in write mode (clear if necessary)
A    Open in append mode (starting from EOF, create a file if necessary)
R +    Open in read/write mode
W +    Open in read/write mode (see W)
A +    Open in read/write mode (see)
RB    Open in binary read mode
WB    Open in binary write mode (see W)
AB    Open in binary append mode (see)
RB +   Open in binary read/write mode (see R +)
WB +   Open in binary read/write mode (see w +)
AB +   Open in binary read/write mode (see A +)

A.    Added in Python 2.3

Link: http://blog.sina.com.cn/s/blog_4ef8be9f0100gdax.html