经常想要用python读取/写入配置文件,正好官方自带的库就提供这了这样的功能。先放官方文档

本文只记录一下最简单的应用,详细的内容需要查阅官方文档。

支持的配置文件格式

最基本的配置文件格式如下所示:

[DEFAULT]
ServerAliveInterval = 45
Compression = yes
CompressionLevel = 9
ForwardX11 = yes
[bitbucket.org]
User = hg
[topsecret.server.com]
Port = 50022 ForwardX11 = no

一个配置文件由若干 [section] 构成,每个 [section] 内包含了若干 key/value 对(用 =: 标示),由 #; 开头的行为注释。

写入配置文件

import configparser
config = configparser.ConfigParser()
config['DEFAULT'] = {'ServerAliveInterval': '45',
                     'Compression': 'yes',
                     'CompressionLevel': '9'}
config['bitbucket.org'] = {}
config['bitbucket.org']['User'] = 'hg'
config['topsecret.server.com'] = {}
topsecret = config['topsecret.server.com']
topsecret['Port'] = '50022'     # mutates the parser
topsecret['ForwardX11'] = 'no'  # same here
config['DEFAULT']['ForwardX11'] = 'yes'
with open('example.ini', 'w') as configfile:
    config.write(configfile)

可以发现,配置文件的结构就像字典,有很多类似的性质。

读取配置文件

>>> config = configparser.ConfigParser()
>>> config.sections()
[]
>>> config.read('example.ini')
['example.ini']
>>> config.sections()
['bitbucket.org', 'topsecret.server.com']
>>> 'bitbucket.org' in config
True
>>> 'bytebong.com' in config
False
>>> config['bitbucket.org']['User']
'hg'
>>> config['DEFAULT']['Compression']
'yes'
>>> topsecret = config['topsecret.server.com']
>>> topsecret['ForwardX11']
'no'
>>> topsecret['Port']
'50022'
>>> for key in config['bitbucket.org']:  
...     print(key)
user
compressionlevel
serveraliveinterval
compression
forwardx11
>>> config['bitbucket.org']['ForwardX11']
'yes'

读取的方法非常直接,需要注意的是 [DEFAULT] 的内容给其他section提供默认值。

API

defaults()

Return a dictionary containing the instance-wide defaults.

sections()

Return a list of the sections available; the default section is not included in the list.

add_section(section)

Add a section named section to the instance. If a section by the given name already exists, DuplicateSectionError is raised. If the default section name is passed, ValueError is raised. The name of the section must be a string; if not, TypeError is raised.

Changed in version 3.2: Non-string section names raise TypeError.

has_section(section)

Indicates whether the named section is present in the configuration. The default section is not acknowledged.

options(section)

Return a list of options available in the specified section.

has_option(section, option)

If the given section exists, and contains the given option, return True; otherwise return False. If the specified section is None or an empty string, DEFAULT is assumed.

read(filenames, encoding=None)

Attempt to read and parse an iterable of filenames, returning a list of filenames which were successfully parsed.

If filenames is a string, a bytes object or a path-like object, it is treated as a single filename. If a file named in filenames cannot be opened, that file will be ignored. This is designed so that you can specify an iterable of potential configuration file locations (for example, the current directory, the user’s home directory, and some system-wide directory), and all existing configuration files in the iterable will be read.

If none of the named files exist, the ConfigParser instance will contain an empty dataset. An application which requires initial values to be loaded from a file should load the required file or files using read_file() before calling read() for any optional files:

import configparser, os

config = configparser.ConfigParser()
config.read_file(open('defaults.cfg'))
config.read(['site.cfg', os.path.expanduser('~/.myapp.cfg')],
            encoding='cp1250')

New in version 3.2: The encoding parameter. Previously, all files were read using the default encoding for open().

New in version 3.6.1: The filenames parameter accepts a path-like object.

New in version 3.7: The filenames parameter accepts a bytes object.

read_file(f, source=None)

Read and parse configuration data from f which must be an iterable yielding Unicode strings (for example files opened in text mode).

Optional argument source specifies the name of the file being read. If not given and f has a name attribute, that is used for source; the default is ”.

New in version 3.2: Replaces readfp().

read_string(string, source=”)

Parse configuration data from a string.

Optional argument source specifies a context-specific name of the string passed. If not given, ” is used. This should commonly be a filesystem path or a URL.

New in version 3.2.

read_dict(dictionary, source=”)

Load configuration from any object that provides a dict-like items() method. Keys are section names, values are dictionaries with keys and values that should be present in the section. If the used dictionary type preserves order, sections and their keys will be added in order. Values are automatically converted to strings.

Optional argument source specifies a context-specific name of the dictionary passed. If not given, is used.

This method can be used to copy state between parsers.

New in version 3.2.

get(section, option, *, raw=False, vars=None[, fallback])

Get an option value for the named section. If vars is provided, it must be a dictionary. The option is looked up in vars (if provided), section, and in DEFAULTSECT in that order. If the key is not found and fallback is provided, it is used as a fallback value. None can be provided as a fallback value.

All the ‘%’ interpolations are expanded in the return values, unless the raw argument is true. Values for interpolation keys are looked up in the same manner as the option.

Changed in version 3.2: Arguments raw, vars and fallback are keyword only to protect users from trying to use the third argument as the fallback fallback (especially when using the mapping protocol).

getint(section, option, *, raw=False, vars=None[, fallback])

A convenience method which coerces the option in the specified section to an integer. See get() for explanation of raw, vars and fallback.

getfloat(section, option, *, raw=False, vars=None[, fallback])

A convenience method which coerces the option in the specified section to a floating point number. See get() for explanation of raw, vars and fallback.

getboolean(section, option, *, raw=False, vars=None[, fallback])

A convenience method which coerces the option in the specified section to a Boolean value. Note that the accepted values for the option are ‘1’, ‘yes’, ‘true’, and ‘on’, which cause this method to return True, and ‘0’, ‘no’, ‘false’, and ‘off’, which cause it to return False. These string values are checked in a case-insensitive manner. Any other value will cause it to raise ValueError. See get() for explanation of raw, vars and fallback.

items(raw=False, vars=None)

items(section, raw=False, vars=None)
When section is not given, return a list of section_name, section_proxy pairs, including DEFAULTSECT.

Otherwise, return a list of name, value pairs for the options in the given section. Optional arguments have the same meaning as for the get() method.

Changed in version 3.8: Items present in vars no longer appear in the result. The previous behaviour mixed actual parser options with variables provided for interpolation.

set(section, option, value)

If the given section exists, set the given option to the specified value; otherwise raise NoSectionError. option and value must be strings; if not, TypeError is raised.

write(fileobject, space_around_delimiters=True)

Write a representation of the configuration to the specified file object, which must be opened in text mode (accepting strings). This representation can be parsed by a future read() call. If space_around_delimiters is true, delimiters between keys and values are surrounded by spaces.

remove_option(section, option)

Remove the specified option from the specified section. If the section does not exist, raise NoSectionError. If the option existed to be removed, return True; otherwise return False.

remove_section(section)

Remove the specified section from the configuration. If the section in fact existed, return True. Otherwise return False.

optionxform(option)

Transforms the option name option as found in an input file or as passed in by client code to the form that should be used in the internal structures. The default implementation returns a lower-case version of option; subclasses may override this or client code can set an attribute of this name on instances to affect this behavior.

You don’t need to subclass the parser to use this method, you can also set it on an instance, to a function that takes a string argument and returns a string. Setting it to str, for example, would make option names case sensitive:

cfgparser = ConfigParser()
cfgparser.optionxform = str

Note that when reading configuration files, whitespace around the option names is stripped before optionxform() is called.

readfp(fp, filename=None)

Deprecated since version 3.2: Use read_file() instead.

Changed in version 3.2: readfp() now iterates on fp instead of calling fp.readline().

For existing code calling readfp() with arguments which don’t support iteration, the following generator may be used as a wrapper around the file-like object:

def readline_generator(fp):
    line = fp.readline()
    while line:
        yield line
        line = fp.readline()

Instead of parser.readfp(fp) use parser.read_file(readline_generator(fp)).

configparser.MAX_INTERPOLATION_DEPTH

The maximum depth for recursive interpolation for get() when the raw parameter is false. This is relevant only when the default interpolation is used.

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