CODEWITHSUNDEEP
pythonfile-ionewline
Federer
Federer

Reputation: 34795

Add new line to head of log file using Python

I'm trying to add a new line in front of a date stamp in a log file. I have the following parts.

Open log file: 

f = open("C:\Users\user\Desktop\Log.file")

Add a new line in front of the date "25/01/2012" (uniquely identifies each log line).

f.write("\n" + "25/01/2012")

Error:

Traceback (most recent call last): 
File "<pyshell#4>", line 1, in <module>
    f.write('\n' + "25/01/2012")
IOError: File not open for writing

Upvotes: 2

Views: 1417

Answers (4)

jon
jon

Reputation: 6246

You need f = open("C:\Users\user\Desktop\Log.file", "w")

http://docs.python.org/tutorial/inputoutput.html#reading-and-writing-files

Hope this helps.

Upvotes: 0

Manse
Manse

Reputation: 38147

f = open("C:\Users\user\Desktop\Log.file","w");

by default 'r' is assumed ie reading docs here

Note: 'w' will overwrite the existing file. Use 'a' to append

Upvotes: 2

C&#233;dric Julien
C&#233;dric Julien

Reputation: 80811

As shown in the python documentation for open(), the default mode is 'r' for reading, not for 'w' for writing. Try to use : 

f = open("C:\Users\user\Desktop\Log.file", 'a')

to open your log file for writing (and not erasing it if it already exists)

Concerning your final goal, that is logging in files, did you have a look to the logging module which will allow you to format all your log record with date, level, PID and many usefull things ?

Upvotes: 6

user647772
user647772

Reputation: 

open("C:\Users\user\Desktop\Log.file", "w")

But please take a look at http://docs.python.org/library/logging.html for logging with Python.

Edit: Even better: http://docs.python.org/howto/logging.html#logging-basic-tutorial

Upvotes: 1

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