你可以这样做

my_string = "false"
val = (my_string == "true")

parens中的位将计算为False。这是另一种不需要进行实际函数调用的方法。

def str2bool(v):
  return v.lower() in ("yes", "true", "t", "1")

然后像这样称呼它:

>>> str2bool("yes")
True
>>> str2bool("no")
False
>>> str2bool("stuff")
False
>>> str2bool("1")
True
>>> str2bool("0")
False

显式处理true和false:

您还可以使函数显式地检查True单词列表和False单词列表。然后，如果它不在两个列表中，则可以抛出异常。

还有一种选择

from ansible.module_utils.parsing.convert_bool import boolean
boolean('no')
# False
boolean('yEs')
# True
boolean('true')
# True

我必须这么做……所以，也许姗姗来迟——但有人可能会发现它很有用

def str_to_bool(input, default):
    """
    | Default | not_default_str | input   | result
    | T       |  "false"        | "true"  |  T
    | T       |  "false"        | "false" |  F
    | F       |  "true"         | "true"  |  T
    | F       |  "true"         | "false" |  F

    """
    if default:
        not_default_str = "false"
    else:
        not_default_str = "true"

    if input.lower() == not_default_str:
        return not default
    else:
        return default

这是我写的版本。将其他几个解决方案合并为一个。

def to_bool(value):
    """
    Converts 'something' to boolean. Raises exception if it gets a string it doesn't handle.
    Case is ignored for strings. These string values are handled:
      True: 'True', "1", "TRue", "yes", "y", "t"
      False: "", "0", "faLse", "no", "n", "f"
    Non-string values are passed to bool.
    """
    if type(value) == type(''):
        if value.lower() in ("yes", "y", "true",  "t", "1"):
            return True
        if value.lower() in ("no",  "n", "false", "f", "0", ""):
            return False
        raise Exception('Invalid value for boolean conversion: ' + value)
    return bool(value)

如果它得到一个字符串，它期望特定的值，否则引发异常。如果它没有得到一个字符串，就让bool构造函数来计算它。测试这些案例:

test_cases = [
    ('true', True),
    ('t', True),
    ('yes', True),
    ('y', True),
    ('1', True),
    ('false', False),
    ('f', False),
    ('no', False),
    ('n', False),
    ('0', False),
    ('', False),
    (1, True),
    (0, False),
    (1.0, True),
    (0.0, False),
    ([], False),
    ({}, False),
    ((), False),
    ([1], True),
    ({1:2}, True),
    ((1,), True),
    (None, False),
    (object(), True),
    ]

该版本保留了int(value)等构造函数的语义，并提供了一种简单的方法来定义可接受的字符串值。

def to_bool(value):
    valid = {'true': True, 't': True, '1': True,
             'false': False, 'f': False, '0': False,
             }   

    if isinstance(value, bool):
        return value

    if not isinstance(value, basestring):
        raise ValueError('invalid literal for boolean. Not a string.')

    lower_value = value.lower()
    if lower_value in valid:
        return valid[lower_value]
    else:
        raise ValueError('invalid literal for boolean: "%s"' % value)


# Test cases
assert to_bool('true'), '"true" is True' 
assert to_bool('True'), '"True" is True' 
assert to_bool('TRue'), '"TRue" is True' 
assert to_bool('TRUE'), '"TRUE" is True' 
assert to_bool('T'), '"T" is True' 
assert to_bool('t'), '"t" is True' 
assert to_bool('1'), '"1" is True' 
assert to_bool(True), 'True is True' 
assert to_bool(u'true'), 'unicode "true" is True'

assert to_bool('false') is False, '"false" is False' 
assert to_bool('False') is False, '"False" is False' 
assert to_bool('FAlse') is False, '"FAlse" is False' 
assert to_bool('FALSE') is False, '"FALSE" is False' 
assert to_bool('F') is False, '"F" is False' 
assert to_bool('f') is False, '"f" is False' 
assert to_bool('0') is False, '"0" is False' 
assert to_bool(False) is False, 'False is False'
assert to_bool(u'false') is False, 'unicode "false" is False'

# Expect ValueError to be raised for invalid parameter...
try:
    to_bool('')
    to_bool(12)
    to_bool([])
    to_bool('yes')
    to_bool('FOObar')
except ValueError, e:
    pass