What's the best practice using a settings file in Python? [closed]
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Improve this questionI have a command line script that I run with a lot of arguments. I have now come to a point where I have too many arguments, and I want to have some arguments in dictionary form too.
So in order to simplify things I would like to run the script with a settings file instead. I don't really know what libraries to use for the parsing of the file. What's the best practice for doing this? I could of course hammer something out myself, but if there is some library for this, I'm all ears.
A few 'demands':
- Rather than using
pickle
I would like it to be a straight forward text file that can easily be read and edited. - I want to be able to add dictionary-like data in it, i.e., some form of开发者_运维知识库 nesting should be supported.
A simplified pseudo example file:
truck:
color: blue
brand: ford
city: new york
cabriolet:
color: black
engine:
cylinders: 8
placement: mid
doors: 2
You can have a regular Python module, say config.py, like this:
truck = dict(
color = 'blue',
brand = 'ford',
)
city = 'new york'
cabriolet = dict(
color = 'black',
engine = dict(
cylinders = 8,
placement = 'mid',
),
doors = 2,
)
and use it like this:
import config
print(config.truck['color'])
The sample config you provided is actually valid YAML. In fact, YAML meets all of your demands, is implemented in a large number of languages, and is extremely human friendly. I would highly recommend you use it. The PyYAML project provides a nice python module, that implements YAML.
To use the yaml module is extremely simple:
import yaml
config = yaml.safe_load(open("path/to/config.yml"))
I Found this the most useful and easy to use https://wiki.python.org/moin/ConfigParserExamples
You just create a "myfile.ini" like:
[SectionOne]
Status: Single
Name: Derek
Value: Yes
Age: 30
Single: True
[SectionTwo]
FavoriteColor=Green
[SectionThree]
FamilyName: Johnson
[Others]
Route: 66
And retrieve the data like:
>>> import ConfigParser
>>> Config = ConfigParser.ConfigParser()
>>> Config
<ConfigParser.ConfigParser instance at 0x00BA9B20>
>>> Config.read("myfile.ini")
['c:\\tomorrow.ini']
>>> Config.sections()
['Others', 'SectionThree', 'SectionOne', 'SectionTwo']
>>> Config.options('SectionOne')
['Status', 'Name', 'Value', 'Age', 'Single']
>>> Config.get('SectionOne', 'Status')
'Single'
Yaml and Json are the simplest and most commonly used file formats to store settings/config. PyYaml can be used to parse yaml. Json is already part of python from 2.5. Yaml is a superset of Json. Json will solve most uses cases except multi line strings where escaping is required. Yaml takes care of these cases too.
>>> import json
>>> config = {'handler' : 'adminhandler.py', 'timeoutsec' : 5 }
>>> json.dump(config, open('/tmp/config.json', 'w'))
>>> json.load(open('/tmp/config.json'))
{u'handler': u'adminhandler.py', u'timeoutsec': 5}
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