I have been reviewing the tutorial for file management in Python 3 but it doesn't mention how to create a file if one doesn't exist. How can I do that?
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1Did you try to use " f = open('workfile', 'w') " and see if python create the file itself ? I know In some languages this is a normal behavior.Russo– Russo2013-04-05 00:08:51 +00:00Commented Apr 5, 2013 at 0:08
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5 Answers
Just open the file in w mode, and it will be created it.
If you want to open an existing file if possible, but create a new file otherwise (and don't want to truncate an existing file), read the paragraph in your link that lists the modes. Or, for complete details, see the open reference docs. For example, if you want to append to the end instead of overwriting from the start, use a.
Comments
Just open the file in write mode:
f = open('fileToWrite.txt', 'w')
Note that this will clobber an existing file. The safest approach is to use append mode:
f = open('fileToWrite.txt', 'a')
As mentioned in this answer, it's generally better to use a with statement to ensure that the file is closed when you have finished with it.
3 Comments
Nathan2055
Right, but even if you use a with statement don't you have to do
f.close() to close the file?
abarnert
@Nathan2055: It's kind of the whole point of
with that you don't need f.close() (or, for other types, lock.release(), etc.)
Platinum Azure
Thanks @jordanm for the edit. I usually do footnote links but I was rushed today.
A new file is only created in write or append modes.
open('file', 'w')
In shell:
$ ls
$ python -c 'open("file", "w")'
$ ls
file
$
Comments
Of course.
with open('newfile.txt', 'w') as f:
f.write('Text in a new file!')
Comments
There are two types of files you can make. a text and a binary.
to make a text file just use file = open('(file name and location goes here).txt', 'w').
to make a binary file you first import pickle, then to put data (like lists numbers ect..) in them you will need to use 'wb' and pickle.dump(data, file_variable) to take out you will need to use 'rb' and pickle.load(file_variable) and give that a variable becuase that is how you refrence the data.
Here is a exaple:
import pickle #bring in pickle
shoplistfile = 'shoplist.data'
shoplist = ['apple', 'peach', 'carrot', 'spice'] #create data
f = open(shoplistfile, 'wb') # the 'wb'
pickle.dump(shoplist, f) #put data in
f.close
del shoplist #delete data
f = open(shoplistfile, 'rb') #open data remember 'rb'
storedlist = pickle.load(f)
print (storedlist) #output
note that if such a file exists it will be writen over.
