Python How would you save a simple settings config file

Question

I don t care if it s JSON  pickle  YAML  or whatever   All other implementations I have seen are not forwards compatible  so if I have a config file  add a new key in the code  then load that config file  it ll just crash   Are there any simple way to do this

User · Answer

Configuration files in python

There are several ways to do this depending on the file format required.

ConfigParser [.ini format]

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 [.json format]

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)

YAML

A basic YAML example is provided in this answer. More details can be found on the pyYAML website.

User · Answer

Save and load a dictionary  You will have arbitrary keys  values and arbitrary number of key  values pairs

User · Answer

try using cfg4py    Hierarchichal design  mulitiple env supported  so never mess up dev settings with production site settings  Code completion  Cfg4py will convert your yaml into a python class  then code completion is available while you typing your code  many more     DISCLAIMER  I m the author of this module

User · Answer

ConfigParser Basic example  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    lt type  str  gt  x user   root    lt type  str  gt  x passwd   my secret password    lt type  str  gt  x db   write-math    lt type  str  gt  Section  other x preprocessing queue     preprocessing scale and center    preprocessing dot reduction    preprocessing connect lines      lt type  str  gt  x use anonymous   yes    lt type  str  gt   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   XML Basic example  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   lt config gt       lt mysql gt           lt host gt localhost lt  host gt           lt user gt root lt  user gt           lt passwd gt my secret password lt  passwd gt           lt db gt write-math lt  db gt       lt  mysql gt       lt other gt           lt preprocessing queue gt               lt li gt preprocessing scale and center lt  li gt               lt li gt preprocessing dot reduction lt  li gt               lt li gt preprocessing connect lines lt  li gt           lt  preprocessing queue gt           lt use anonymous value  true    gt       lt  other gt   lt  config gt

User · Answer

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

User · Answer

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

[python] Python: How would you save a simple settings/config file?

Configuration files in python

ConfigParser [.ini format]

JSON [.json format]

YAML

Examples related to python

Examples related to json

Examples related to settings

Examples related to config

Examples related to ini