CODEWITHSUNDEEP
python
rocksNwaves
rocksNwaves

Reputation: 6164

Is it good practice to open a file for reading, get the data, close it and then reopen it for writing?

So I'm learning about reading and writing from file in python. I seem to understand that if you use 'w' in order to open an existing file for writing, it will overwrite that file. So right now, I am doing something like this:

with open('something.json', 'r') as open_file:
    get some stuff

with open('something.json', 'w') as open_file:
    add some stuff

Is it normal to open and close the file twice in order to both read and write, or is there an optional argument that might allow me to do everything all at once?

Upvotes: 1

Views: 1635

Answers (2)

bearrito
bearrito

Reputation: 2315

Your approach is pythonic and I would consider it a good practice.

Consider something like the following

with open('something.json', 'r+') as open_file:
  data =  open_file.read()
  ... computation with the data ...
  output = ...
  open_file.write(output)

Upvotes: 1

Nikaido
Nikaido

Reputation: 4629

It depends on what you need to do. If you need to read and write it is better to do everything with a single with statement. In this way you are not doing extra work to reopen the file (e.g loading the file descriptor in memory).

There are different options depending on what you need to do for the with open statement:

  • r+ Open for reading and writing. The stream is positioned at the beginning of the file.

  • a+ Open for reading and appending (writing at end of file). The initial file position for reading is at the beginning of the file, but output is appended to the end of the file (but in some Unix systems regardless of the current seek position).

Upvotes: 4

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