How to print the console to a text file AFTER the program finishes (Python)?

Question

I have a program that outputs many calculations and results to the console through the print statement. I want to write some code to export (or save) all the contents of the console to a simple text file.

I searched StackOverflow and other sites but I found some methods to redirect the print statement to print to a file directly, but I want the program to work normally, to display outputs to the console, then to save its contents AFTER all operations of the program done.

I am using PyCharm with Python2.7 if it matters

Answer 1

Ok, so normally to get it done, you have to rewrite python print built-in function. But... There is ipython, which provides some hooks.

First you need to have ipython installed:

#bash
sudo pip install ipython

(I'm using sudo to simple locate then folder I need to reach, read further)

After ipython installation you'll have ipython extensions folder available, so get to it:

#bash
cd ~/.ipython/extensions/

and create there let's say a file called print_to_file.py, here is its content:

#python
class PrintWatcher(object):
    def __init__(self, ip):
        self.shell = ip

    def post_execute(self):
        with open('/home/turkus/shell.txt', 'a+') as f:
            in_len = len(self.shell.user_ns['In'])
            i = in_len - 1

            in_ = self.shell.user_ns['In'][i]
            out = self.shell.user_ns['Out'].get(i, '')
            # you can edit this line if you want different input in shell.txt
            f.write('{}\n{}\n'.format(in_, out))


def load_ipython_extension(ip):
    pw = PrintWatcher(ip)
    ip.events.register('post_run_cell', pw.post_execute)

After saving a file just run:

#bash
ipython profile create 

# you will get something like that:
[ProfileCreate] Generating default config file: u'/home/turkus/.ipython/profile_default/ipython_config.py'

Now get back to setting up our hook. We must open ipython_config.py created under path above and put there some magic (there is a lot of stuff there, so go to the end of file):

# some commented lines here
c = get_config()
c.InteractiveShellApp.extensions = [
    'print_to_file'
]

After saving it, you can run ipython and write your code. Every your input will be written in a file under path you provided above, in my case it was:

/home/turkus/shell.txt

Notes

You can avoid loading your extension every time ipython fires up, by just delete 'print_to_file' from c.InteractiveShellApp.extensions list in ipython_config.py. But remember that you can load it anytime you need, just by typing in ipython console:

➜  ~ ipython
Python 2.7.12 (default, Jul  1 2016, 15:12:24) 
Type "copyright", "credits" or "license" for more information.

IPython 4.0.0 -- An enhanced Interactive Python.
?         -> Introduction and overview of IPython's features.
%quickref -> Quick reference.
help      -> Python's own help system.
object?   -> Details about 'object', use 'object??' for extra details.

In [1]: %load_ext print_to_file

Any change in print_to_file.py is being reflected in open ipython shell after using %reload_ext print_to_file command, so you don't have to exit from and fire up it again.

Answer 2

I am unsure how you could receive the contents of a console for any editor however this can be achieved quite simply by replacing your print() statements with .write

class Writer(object):
    def __init__(self, out_file, overwrite=False):
        self.file_name = out_file
        self.overwrite = overwrite
        self.history = []

    def write(self, statement):
        self.history.append(statement)
        print statement

    def close(self):
        if self.overwrite:
            self.out_file = open(self.file_name, 'wb')
        else:
            self.out_file = open(self.file_name, 'ab')
        for x in self.history:
            self.out_file.write(x+'/n')
        self.out_file.close()
        self.history = []

p = Writer('my_output_file.txt')
p.write('my string to print and save!') 
p.close() #close the writer to save the contents to a file before exiting

Answer 3

After I know understood your question I think you search the tee command

python your_program | tee output.txt

This will show you the output both, in the console and in output.txt

PS: Since you did not answer to my comment which OS you use I assumed that you use either Linux or MACOS. Should work on both. I don't know how to do this on windows...