= Python ConfigParser =

'''`configparser`''' is a module that supports (de-)serializing configuration files.

Note that, in Python 2, the module's name was `ConfigParser`.

The configuration language is based on (but not exactly the same as) the [[Windows]] INI file.

<<TableOfContents>>

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== Configuration Language ==



=== Sections ===

All options must be set under a '''section header'''. Section headers cannot be repeated, or the parser will raise `configparser.DuplicateSectionError`.

{{{
[Section1]
option=1

[Section2]
option=2
}}}



=== Options and Values ===

Configurations are composed of '''options''' and '''values''', both of which are parsed as strings. The option and value parts are delimited by either equals signs (`=`) or colons (`:`). Spaces around the delimiter are ignored, but all other spaces are retained in the option and value.

{{{
[Section]
foo=1
bar=abc
}}}

Options must be set with a value or `configparser.ParsingError` will be raised. An empty value (i.e. a delimiter with no righthand side value) is valid. In this case, options are set to `''`.

{{{
[Section]
baz=
}}}

This can be altered by setting `allow_no_value=True` on the parser. In this case, options are set to `None`.

{{{
[Section]
keyword-instruction
}}}

Options must be unique within a section or `configparser.DuplicateOptionError` will be raised.



=== Defaults ===

Default options and values can be in a `DEFAULT` section.

The name of this section can be adjusted by setting the parser's `default_section` argument or by setting the `configparser.DEFAULTSECT` constant.

{{{
[DEFAULT]
foo = 1
}}}



=== Interpolation ===

Configuration can be written with variables by setting the parser's `interpolation` argument, as with `interpolation=configparser.BasicInterpolation()`.

{{{
[Section]
user dir   = /Users
my dir = %(my dir)s/me
}}}

----



== Usage ==

{{{
import configparser
c = configparser.ConfigParser()
c.read('example.ini')
}}}

The configuration API mirrors that of dictionaries.

{{{
c.get('Section', 'option')
c.get('Section', 'option', fallback=False)
c['Section']['option']
}}}



=== Sections ===

Sections of configuration can be accessed with `parser['section']`. This returns a proxy for the internal data structure. If values are set (or changed) in either the configuration or section, the other also updates.

The configuration section API matches that of dictionaries.

{{{
s = c['section']
s.get('option', False)
}}}



=== Helper Methods ===

{{{
c.getint('section', 'option')
c.getfloat('section', 'option')
c.getboolean('section', 'option')
}}}

`getboolean` is particularly useful; it interprets a variety of string values as boolean values: `true` and `false`, `yes` and `no`, `on` and `off`, `1` and `0`.



=== Default Values ===

Parser defaults are set at creation.

{{{
c = configparser.ConfigParser({'foo': 'bar'})
}}}

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== See also ==

[[https://docs.python.org/3/library/configparser.html|Python configparser module documentation]]

[[https://pymotw.com/3/configparser/|Python Module of the Day article for configparser]]



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