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In python, I want to open a file if already exists or create it if it doesnt exist. also i want to write to the file new contents on opening it without overwriting the existing contents of the file. How can I do it?

rkatkam
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    is there anything you have done so far? – Lafexlos Mar 12 '14 at 10:11
  • yes, I used like f=open(file1,'w+') that creates a file and i am nt able to make out whether it is opening the file if exists because the read()operation is ain't working since i opened in 'W' mode. and now if i write anything its overwriting the contents – rkatkam Mar 12 '14 at 10:16
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    `file_object = open('my_file.txt', mode='a+')` – Trimax Mar 12 '14 at 10:17
  • wowww. Thanks Trimax, its working!! – rkatkam Mar 12 '14 at 10:21
  • possible duplicate of [How do you append to file in python?](http://stackoverflow.com/questions/4706499/how-do-you-append-to-file-in-python) – DNA Mar 12 '14 at 10:53
  • my question was how to create a file if doesnt exists and open the same file if it exists. – rkatkam Mar 12 '14 at 14:32

2 Answers2

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PEP8 suggests you to use:

with open('test.txt', 'a+') as f:
    f.write( "Your new content" )

The with statement is better because it will ensure you always close the file, even if an exception is raised.

Example adapted from: http://docs.python-guide.org/en/latest/writing/style/#pep-8

abrunet
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0

You can use:

file = open('myfile.dat', 'a+')

Refer to this link for details: http://docs.python.org/2/tutorial/inputoutput.html

Shah
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