How to handle empty values in config files with ConfigParser?

Question

How can I parse tags with no value in an ini file with python configparser module?

For example, I have the following ini and I need to parse rb. In some ini files rb has integer values and on some no value at all like the example below. How can I do that with configparser without getting a valueerror? I use the getint function

[section]
person=name
id=000
rb=

Answer 1

创建解析器对象时，您需要设置allow_no_value=True可选参数。

Answer 2

Maybe use a try...except block:

    try:
        value=parser.getint(section,option)
    except ValueError:
        value=parser.get(section,option)

For example:

import ConfigParser

filename='config'
parser=ConfigParser.SafeConfigParser()
parser.read([filename])
print(parser.sections())
# ['section']
for section in parser.sections():
    print(parser.options(section))
    # ['id', 'rb', 'person']
    for option in parser.options(section):
        try:
            value=parser.getint(section,option)
        except ValueError:
            value=parser.get(section,option)
        print(option,value,type(value))
        # ('id', 0, <type 'int'>)
        # ('rb', '', <type 'str'>)
        # ('person', 'name', <type 'str'>) 
print(parser.items('section'))
# [('id', '000'), ('rb', ''), ('person', 'name')]

Answer 3

Instead of using getint() , use get() to get the option as a string. Then convert to an int yourself:

rb = parser.get("section", "rb")
if rb:
    rb = int(rb)

Answer 4

Since there is still an unanswered question about python 2.6, the following will work with python 2.7 or 2.6. This replaces the internal regex used to parse the option, separator, and value in ConfigParser.

def rawConfigParserAllowNoValue(config):
    '''This is a hack to support python 2.6. ConfigParser provides the 
    option allow_no_value=True to do this, but python 2.6 doesn't have it.
    '''
    OPTCRE_NV = re.compile(
        r'(?P<option>[^:=\s][^:=]*)'    # match "option" that doesn't start with white space
        r'\s*'                          # match optional white space
        r'(?P<vi>(?:[:=]|\s*(?=$)))\s*' # match separator ("vi") (or white space if followed by end of string)
        r'(?P<value>.*)$'               # match possibly empty "value" and end of string
    )
    config.OPTCRE = OPTCRE_NV
    config._optcre = OPTCRE_NV
    return config

Use as

    fp = open("myFile.conf")
    config = ConfigParser.RawConfigParser()
    config = rawConfigParserAllowNoValue(config)

Side Note

There is a OPTCRE_NV in ConfigParser for Python 2.7, but if we used it in the above function exactly, the regex would return None for vi and value, which causes ConfigParser to fail internally. Using the function above returns a blank string for vi and value and everyone is happy.

Answer 5

Why not comment out the rb option like so:

[section]
person=name
id=000
; rb=

and then use this awesome oneliner:

rb = parser.getint('section', 'rb') if parser.has_option('section', 'rb') else None