Help: How to validate a dict with at least one of a set of keys?

[cuteufo]

I have a not so ideal validator like:

sch = Schema({
    'a': str,
    'b': int,
    Option('c'): str,
    Option('d'): int
}

in which, a and b must exist, while c or d may or may not exist. It will be fine if neither c nor d shows up. And please also note that c and d's value are of different type.

How can I validate a dict that a and b must exist, while at least one of c and d should exist? I thought of replacing the two Option()s to Regex("c|d"), but was not able to specify the data type according its key value.

Any advice is appreciated.

[HansBambel]

I want to do something similar. I would like to validate that I have at least one entry:

at_least_one = Schema(
    {
        Optional("a"): Use(int),
        Optional("b"): Use(int),
        Optional("c"): Use(int),
        Optional("d"): Use(int),
        Optional("e"): Use(int),
        Optional("f"): Use(int),
    }
)

Therefore, I want a Schema that renders at_least_one.is_valid({}) to false, but at_least_one.is_valid({"a": 1}) to true.

[harismuzaffer]

I'm facing the same issue. Anyone able to solve this?

[tivaliy]

Ok, here is what you can try to use:

schema = Schema(
    And({
        # First name
        Optional('foo'): str,
        # Second name
        Optional('bar'): str
    }, lambda d: bool(d))
)
schema.validate({})
...
>> SchemaError: <lambda>({}) should evaluate to True

[harismuzaffer]

Ok, here is what you can try to use:

schema = Schema(
    And({
        # First name
        Optional('foo'): str,
        # Second name
        Optional('bar'): str
    }, lambda d: bool(d))
)
schema.validate({})
...
>> SchemaError: <lambda>({}) should evaluate to True

This is helpful but doesn't solve the problem. Apart from foo and bar, if we have a required key in the dict, this won't work

E.g I want to validate {"name": "haris", "foo": "foo value"} such thatname is mandatory whileas out of foo and bar one has to be there, then how would you modify the schema?

[tivaliy]

Ok, here is what you can try to use:

schema = Schema(
    And({
        # First name
        Optional('foo'): str,
        # Second name
        Optional('bar'): str
    }, lambda d: bool(d))
)
schema.validate({})
...
>> SchemaError: <lambda>({}) should evaluate to True

This is helpful but doesn't solve the problem. Apart from foo and bar, if we have a required key in the dict, this won't work

E.g I want to validate {"name": "haris", "foo": "foo value"} such thatname is mandatory whileas out of foo and bar one has to be there, then how would you modify the schema?

How about this one:

In [34]: schema = Schema(
    ...:     And({
    ...:         'required': str,
    ...:         Optional('foo'): str,
    ...:         Optional('bar'): str
    ...:     }, lambda d: any(k in d for k in ('foo', 'bar')), error="Along with required attributes at least 'foo' or 'bar' must be specified"),
    ...: )