Generating python files with fixed code in them

Question

in my everyday job I write different models and for each model I need to create a python file like this:

class SomeModel:
    def define_params(self):
        return

    def define_input(self):
        return

    def run_model(self):
        return

I want to write a python script which will create a file with this format.

I tried:

import os

path = 'path_tol_folder_in_which_to_store_the_file'

if not os.path.exists(path):
os.makedirs(path)

with open(os.path.join(path, 'some_model.py'), 'w') as some_model:
some_model.writelines(
'class SomeModel:'
'    def define_params(csv):'
'        csv = ("PD", STRING)'
'        return csv'
)

When I run this code, the file is created but in there there is only one line:

class SomeModel: def define_params(csv): csv = ("PD", STRING) return csv (imagine this is one line)

and when I do ctrl+alt+L (format code) it does not format the code the way it should be.

Is there a way to do this so that the code format in the file is correct, i.e.

class SomeModel:
    def define_params(csv):
        csv = ("PD", STRING)
        return csv

Thanks

just a thought. You could inherit from a parent class. The parent class has methods for parameter and states definition. In the child class you only define the run method. — Moritz
– Moritz, Commented Dec 8, 2019 at 16:27

Thierry Lathuille · Accepted Answer · 2019-12-08 16:15:17Z

1

writelines expects an iterable of strings (but will also accept a single string, as it does here), and what you passed is actually a single string: Python implicitely concatenates strings that are separated by whitespace (spaces, newlines...)

>>> 'abc'    'def'
'abcdef'

You could pass it a list of strings (note the [] and commas separating the strings), but you would have to explicitely include a newline \n at the end of each line:

some_model.writelines([
'class SomeModel:\n',
'    def define_params(csv):\n',
'        csv = ("PD", STRING)\n',
'        return csv'
])

or more simply, a multiline string:

some_model.write("""
class SomeModel:
    def define_params(csv):
        csv = ("PD", STRING)
        return csv
""")

edited Dec 8, 2019 at 16:15

answered Dec 8, 2019 at 16:09

Thierry Lathuille

24.4k10 gold badges49 silver badges57 bronze badges

Sign up to request clarification or add additional context in comments.

5 Comments

Mad Physicist Over a year ago

writelines still requires newlines at the end of each line.

Thierry Lathuille Over a year ago

@MadPhysicist Oh, yes.. :/

Mad Physicist Over a year ago

Just slap x + '\n' for x in before your list

Thierry Lathuille Over a year ago

Yes... That is just so much easier to use triple quotes here...

Ivan Ivanov Over a year ago

The tripple quotes help. Thanks a lot!

norok2 · Accepted Answer · 2019-12-08 16:16:26Z

1

Use triple quotes, which preserve blanks:

some_model.write(
'''class SomeModel:
    def define_params(csv):
        csv = ("PD", STRING)
        return csv
'''
)

edited Dec 8, 2019 at 16:16

answered Dec 8, 2019 at 16:07

norok2

27.1k6 gold badges83 silver badges110 bronze badges

2 Comments

Mad Physicist Over a year ago

writelines expects an iterable of strings ending in newlines. This magically works because strings are iterable, but you should really be calling write instead.

norok2 Over a year ago

@MadPhysicist Right, it's copy-paste mistake :-)

Collectives™ on Stack Overflow

Generating python files with fixed code in them

2 Answers 2

5 Comments

2 Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

5 Comments

2 Comments

Your Answer

Sign up or log in

Post as a guest

Related