Introduction
I want to write a demo for login and registration, but the previous demo data is written in the program, and the data is not saved every time the program is closed. .
So I thought about writing to the configuration file.
Python itself provides a Module-configparser to read and write configuration files.
Configuration file parser.
A configuration file consists of sections, lead by a “[section]” header,
and followed by “name: value” entries, with continuations and such in
the style of RFC 822.
Note The ConfigParser module has been renamed to configparser in Python 3. The 2to3 tool will automatically adapt imports when converting your sources to Python 3.
In py2, the module is called ConfigParser, and in py3, the letters are all lowercase. This article takes py3 as an example
class
Properties and methods of ConfigParser
ConfigParser -- responsible for parsing a list of
configuration files, and managing the parsed database.
methods:
__init__(defaults=None, dict_type=_default_dict, allow_no_value=False,
delimiters=('=', ':'), comment_prefixes=('#', ';'),
inline_comment_prefixes=None, strict=True,
empty_lines_in_values=True, default_section='DEFAULT',
interpolation=<unset>, converters=<unset>):
Create the parser. When `defaults' is given, it is initialized into the
dictionary or intrinsic defaults. The keys must be strings, the values
must be appropriate for %()s string interpolation.
When `dict_type' is given, it will be used to create the dictionary
objects for the list of sections, for the options within a section, and
for the default values.
When `delimiters' is given, it will be used as the set of substrings
that divide keys from values.
When `comment_prefixes' is given, it will be used as the set of
substrings that prefix comments in empty lines. Comments can be
indented.
When `inline_comment_prefixes' is given, it will be used as the set of
substrings that prefix comments in non-empty lines.
When `strict` is True, the parser won't allow for any section or option
duplicates while reading from a single source (file, string or
dictionary). Default is True.
When `empty_lines_in_values' is False (default: True), each empty line
marks the end of an option. Otherwise, internal empty lines of
a multiline option are kept as part of the value.
When `allow_no_value' is True (default: False), options without
values are accepted; the value presented for these is None.
When `default_section' is given, the name of the special section is
named accordingly. By default it is called ``"DEFAULT"`` but this can
be customized to point to any other valid section name. Its current
value can be retrieved using the ``parser_instance.default_section``
attribute and may be modified at runtime.
When `interpolation` is given, it should be an Interpolation subclass
instance. It will be used as the handler for option value
pre-processing when using getters. RawConfigParser objects don't do
any sort of interpolation, whereas ConfigParser uses an instance of
BasicInterpolation. The library also provides a ``zc.buildbot``
inspired ExtendedInterpolation implementation.
When `converters` is given, it should be a dictionary where each key
represents the name of a type converter and each value is a callable
implementing the conversion from string to the desired datatype. Every
converter gets its corresponding get*() method on the parser object and
section proxies.
sections()
Return all the configuration section names, sans DEFAULT.
has_section(section)
Return whether the given section exists.
has_option(section, option)
Return whether the given option exists in the given section.
options(section)
Return list of configuration options for the named section.
read(filenames, encoding=None)
Read and parse the iterable of named configuration files, given by
name. A single filename is also allowed. Non-existing files
are ignored. Return list of successfully read files.
read_file(f, filename=None)
Read and parse one configuration file, given as a file object.
The filename defaults to f.name; it is only used in error
messages (if f has no `name' attribute, the string `<???>' is used).
read_string(string)
Read configuration from a given string.
read_dict(dictionary)
Read configuration from a dictionary. 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.
get(section, option, raw=False, vars=None, fallback=_UNSET)
Return a string value for the named option. All % interpolations are
expanded in the return values, based on the defaults passed into the
constructor and the DEFAULT section. Additional substitutions may be
provided using the `vars' argument, which must be a dictionary whose
contents override any pre-existing defaults. If `option' is a key in
`vars', the value from `vars' is used.
getint(section, options, raw=False, vars=None, fallback=_UNSET)
Like get(), but convert value to an integer.
getfloat(section, options, raw=False, vars=None, fallback=_UNSET)
Like get(), but convert value to a float.
getboolean(section, options, raw=False, vars=None, fallback=_UNSET)
Like get(), but convert value to a boolean (currently case
insensitively defined as 0, false, no, off for False, and 1, true,
yes, on for True). Returns False or True.
items(section=_UNSET, raw=False, vars=None)
If section is given, return a list of tuples with (name, value) for
each option in the section. Otherwise, return a list of tuples with
(section_name, section_proxy) for each section, including DEFAULTSECT.
remove_section(section)
Remove the given file section and all its options.
remove_option(section, option)
Remove the given option from the given section.
set(section, option, value)
Set the given option.
write(fp, space_around_delimiters=True)
Write the configuration state in .ini format. If
`space_around_delimiters' is True (the default), delimiters
between keys and values are surrounded by spaces.
Data format of the configuration file
The following config.ini shows the data format of the configuration file, enclosed in square brackets [] is a section such as Default, Color; each section has multiple options, such as serveraliveinterval, compression, etc.
Option is where we save our own data, similar to the key-value pair optionname = value or optionname: value (it can also be set to allow null values)
[Default]
serveraliveinterval = 45
compression = yes
compressionlevel = 9
forwardx11 = yes
values like this: 1000000
or this: 3.14159265359
[No Values]
key_without_value
empty string value here =
[Color]
isset = true
version = 1.1.0
orange = 150,100,100
lightgreen = 0,220,0
type of data
In the data saved by py configparser, the value of value is saved as a string type, and you need to convert it to the data type you need.
Config parsers do not guess datatypes of values in configuration files, always storing them internally as strings. This means that if you need other datatypes, you should convert on your own:
E.g
>>> int(topsecret['Port'])
50022
>>> float(topsecret['CompressionLevel'])
9.0
Commonly used method
Open the configuration file
import configparser
file = 'config.ini'
# 创建配置文件对象
cfg = configparser.ConfigParser(comment_prefixes='#')
# 读取配置文件
cfg.read(file, encoding='utf-8')
Only open here, do not do anything to read and change
Read all sections of the configuration file
Replace the file with the corresponding configuration file
import configparser
file = 'config.ini'
cfg = configparser.ConfigParser(comment_prefixes='#')
cfg.read(file, encoding='utf-8')
# 获取所有section
sections = cfg.sections()
# 显示读取的section结果
print(sections)
Determine if there is a corresponding section!!!
The program will end abnormally when there is no corresponding section to operate directly
import configparser
file = 'config.ini'
cfg = configparser.ConfigParser(comment_prefixes='#')
cfg.read(file, encoding='utf-8')
if cfg.has_section("Default"): # 有没有"Default" section
print("存在Defaul section")
else:
print("不存在Defaul section")
Determine the corresponding Option under the section
import configparser
file = 'config.ini'
cfg = configparser.ConfigParser(comment_prefixes='#')
cfg.read(file, encoding='utf-8')
# 检测Default section下有没有"CompressionLevel" option
if cfg.cfg.has_option('Default', 'CompressionLevel'):
print("存在CompressionLevel option")
else:
print("不存在CompressionLevel option")
Add section and option
The most important thing: Finally, be sure to write a file to save! ! ! Otherwise, the result of program modification will not be modified into the file
- Before adding a section, check whether it exists, otherwise if there is a duplicate name, an error will be reported and the program will end abnormally
- Make sure the section exists before adding option, otherwise the same as 1.
The option will be created if the option does not exist when the option is modified
import configparser
file = 'config.ini'
cfg = configparser.ConfigParser(comment_prefixes='#')
cfg.read(file, encoding='utf-8')
if not cfg.has_section("Color"): # 不存在Color section就创建
cfg.add_section('Color')
# 设置sectin下的option的value，如果section不存在就会报错
cfg.set('Color', 'isset', 'true')
cfg.set('Color', 'version', '1.1.0')
cfg.set('Color', 'orange', '150,100,100')
# 把所作的修改写入配置文件
with open(file, 'w', encoding='utf-8') as configfile:
cfg.write(configfile)
Delete option
import configparser
file = 'config.ini'
cfg = configparser.ConfigParser(comment_prefixes='#')
cfg.read(file, encoding='utf-8')
cfg.remove_option('Default', 'CompressionLevel'
# 把所作的修改写入配置文件
with open(file, 'w', encoding='utf-8') as configfile:
cfg.write(configfile)
Delete section
When deleting a section, all options below the section will be automatically deleted recursively, use it with caution
import configparser
file = 'config.ini'
cfg = configparser.ConfigParser(comment_prefixes='#')
cfg.read(file, encoding='utf-8')
cfg.remove_section('Default')
# 把所作的修改写入配置文件
with open(file, 'w', encoding='utf-8') as configfile:
cfg.write(configfile)
Instance
Create a configuration file
import configparser
file = 'config.ini'
# 创建配置文件对象
cfg = configparser.ConfigParser(comment_prefixes='#')
# 读取配置文件
cfg.read(file, encoding='utf-8')```
# 实例
## 创建一个配置文件
下面的demo介绍了如何检测添加section和设置value
```python
#!/usr/bin/env python
# -*- encoding: utf-8 -*-
'''
@File : file.py
@Desc : 使用configparser读写配置文件demo
@Author : Kearney
@Contact : [email protected]
@Version : 0.0.0
@License : GPL-3.0
@Time : 2020/10/20 10:23:52
'''
import configparser
file = 'config.ini'
# 创建配置文件对象
cfg = configparser.ConfigParser(comment_prefixes='#')
# 读取配置文件
cfg.read(file, encoding='utf-8')
if not cfg.has_section("Default"): # 有没有"Default" section
cfg.add_section("Default") # 没有就创建
# 设置"Default" section下的option的value
# 如果这个section不存在就会报错，所以上面要检测和创建
cfg.set('Default', 'ServerAliveInterval', '45')
cfg.set('Default', 'Compression', 'yes')
cfg.set('Default', 'CompressionLevel', '9')
cfg.set('Default', 'ForwardX11', 'yes')
if not cfg.has_section("Color"): # 不存在Color就创建
cfg.add_section('Color')
# 设置sectin下的option的value，如果section不存在就会报错
cfg.set('Color', 'isset', 'true')
cfg.set('Color', 'version', '1.1.0')
cfg.set('Color', 'orange', '150,100,100')
cfg.set('Color', 'lightgreen', '0,220,0')
if not cfg.has_section("User"):
cfg.add_section('User')
cfg.set('User', 'iscrypted', 'false')
cfg.set('User', 'Kearney', '[email protected]')
cfg.set('User', 'Tony', '[email protected]')
# 把所作的修改写入配置文件，并不是完全覆盖文件
with open(file, 'w', encoding='utf-8') as configfile:
cfg.write(configfile)
Running the above program will create a config.ini configuration file, and then add the section and option-value
file contents as shown below
[Default]
serveraliveinterval = 45
compression = yes
compressionlevel = 9
forwardx11 = yes
[Color]
isset = true
version = 1.1.0
orange = 150,100,100
lightgreen = 0,220,0
[User]
iscrypted = false
kearney = [email protected]
tony = [email protected]