There are several ways to do this depending on the file format required.
I would use the standard configparser approach unless there were compelling reasons to use a different format.
Write a file like so:
# python 2.x
# from ConfigParser import SafeConfigParser
# config = SafeConfigParser()
# python 3.x
from configparser import ConfigParser
config = ConfigParser()
config.read('config.ini')
config.add_section('main')
config.set('main', 'key1', 'value1')
config.set('main', 'key2', 'value2')
config.set('main', 'key3', 'value3')
with open('config.ini', 'w') as f:
config.write(f)
The file format is very simple with sections marked out in square brackets:
[main]
key1 = value1
key2 = value2
key3 = value3
Values can be extracted from the file like so:
# python 2.x
# from ConfigParser import SafeConfigParser
# config = SafeConfigParser()
# python 3.x
from configparser import ConfigParser
config = ConfigParser()
config.read('config.ini')
print(config.get('main', 'key1')) # -> "value1"
print(config.get('main', 'key2')) # -> "value2"
print(config.get('main', 'key3')) # -> "value3"
# getfloat() raises an exception if the value is not a float
a_float = config.getfloat('main', 'a_float')
# getint() and getboolean() also do this for their respective types
an_int = config.getint('main', 'an_int')
JSON data can be very complex and has the advantage of being highly portable.
Write data to a file:
import json
config = {"key1": "value1", "key2": "value2"}
with open('config1.json', 'w') as f:
json.dump(config, f)
Read data from a file:
import json
with open('config.json', 'r') as f:
config = json.load(f)
#edit the data
config['key3'] = 'value3'
#write it back to the file
with open('config.json', 'w') as f:
json.dump(config, f)
A basic YAML example is provided in this answer. More details can be found on the pyYAML website.
The file can be loaded and used like this:
#!/usr/bin/env python
import ConfigParser
import io
# Load the configuration file
with open("config.yml") as f:
sample_config = f.read()
config = ConfigParser.RawConfigParser(allow_no_value=True)
config.readfp(io.BytesIO(sample_config))
# List all contents
print("List all contents")
for section in config.sections():
print("Section: %s" % section)
for options in config.options(section):
print("x %s:::%s:::%s" % (options,
config.get(section, options),
str(type(options))))
# Print some contents
print("\nPrint some contents")
print(config.get('other', 'use_anonymous')) # Just get the value
print(config.getboolean('other', 'use_anonymous')) # You know the datatype?
which outputs
List all contents
Section: mysql
x host:::localhost:::<type 'str'>
x user:::root:::<type 'str'>
x passwd:::my secret password:::<type 'str'>
x db:::write-math:::<type 'str'>
Section: other
x preprocessing_queue:::["preprocessing.scale_and_center",
"preprocessing.dot_reduction",
"preprocessing.connect_lines"]:::<type 'str'>
x use_anonymous:::yes:::<type 'str'>
Print some contents
yes
True
As you can see, you can use a standard data format that is easy to read and write. Methods like getboolean and getint allow you to get the datatype instead of a simple string.
Writing configuration
import os
configfile_name = "config.yaml"
# Check if there is already a configurtion file
if not os.path.isfile(configfile_name):
# Create the configuration file as it doesn't exist yet
cfgfile = open(configfile_name, 'w')
# Add content to the file
Config = ConfigParser.ConfigParser()
Config.add_section('mysql')
Config.set('mysql', 'host', 'localhost')
Config.set('mysql', 'user', 'root')
Config.set('mysql', 'passwd', 'my secret password')
Config.set('mysql', 'db', 'write-math')
Config.add_section('other')
Config.set('other',
'preprocessing_queue',
['preprocessing.scale_and_center',
'preprocessing.dot_reduction',
'preprocessing.connect_lines'])
Config.set('other', 'use_anonymous', True)
Config.write(cfgfile)
cfgfile.close()
results in
[mysql]
host = localhost
user = root
passwd = my secret password
db = write-math
[other]
preprocessing_queue = ['preprocessing.scale_and_center', 'preprocessing.dot_reduction', 'preprocessing.connect_lines']
use_anonymous = True
Seems not to be used at all for configuration files by the Python community. However, parsing / writing XML is easy and there are plenty of possibilities to do so with Python. One is BeautifulSoup:
from BeautifulSoup import BeautifulSoup
with open("config.xml") as f:
content = f.read()
y = BeautifulSoup(content)
print(y.mysql.host.contents[0])
for tag in y.other.preprocessing_queue:
print(tag)
where the config.xml might look like this
<config>
<mysql>
<host>localhost</host>
<user>root</user>
<passwd>my secret password</passwd>
<db>write-math</db>
</mysql>
<other>
<preprocessing_queue>
<li>preprocessing.scale_and_center</li>
<li>preprocessing.dot_reduction</li>
<li>preprocessing.connect_lines</li>
</preprocessing_queue>
<use_anonymous value="true" />
</other>
</config>
If you want to use something like an INI file to hold settings, consider using configparser which loads key value pairs from a text file, and can easily write back to the file.
INI file has the format:
[Section]
key = value
key with spaces = somevalue
Try using ReadSettings:
from readsettings import ReadSettings
data = ReadSettings("settings.json") # Load or create any json, yml, yaml or toml file
data["name"] = "value" # Set "name" to "value"
data["name"] # Returns: "value"
For a simple configuration file, I prefer JSON file, e.g. conf.json:
{
"version": 1,
"bind": {
"address": "127.0.0.1",
"port": 8080
},
"data": {
"a": [1, 2, 3],
"b": 2.5
}
}
Then load it using JSON library:
import json
with open('conf.json', 'r') as f:
confjson = Configuration(json.loads(f.read()))
Lastly, convert it to this custom dictionary class:
class Configuration(dict):
def __init__(self, *args):
super(Configuration, self).__init__()
for arg in args:
for key, value in arg.items():
value = Configuration(value) if isinstance(value, dict) else value
self.__setattr__(key, value)
def __getattr__(self, attr):
return self.get(attr)
def __setattr__(self, key, value):
self.__setitem__(key, value)
def __setitem__(self, key, value):
super(Configuration, self).__setitem__(key, value)
self.__dict__.update({key: value})
def __delattr__(self, item):
self.__delitem__(item)
def __delitem__(self, key):
super(Configuration, self).__delitem__(key)
del self.__dict__[key]
conf = Configuration(confjson)
Now you can access your configuration using dot "." e.g.:
print(conf.version)
print(conf.bind.address)
print(conf.bind.port)
print(conf.data.a)
print(conf.data.a)
try using cfg4py:
DISCLAIMER: I'm the author of this module
.ini-like format of theconfigparsermodule should do what you want. - Bakuriu