Lambdas

Several library methods take a lambda to filter, project, or otherwise refine data. A lambda declares one or more range variables, separated by semicolons, then a colon and a body expression:

@x: @x.price > 10

@acc;@current: @acc + @current

A lambda’s variables exist only inside its body.

Example

transformer.json

{
    "hasValues": "#valueOf($.some.integerArray)->#any(@x: @x > 5)",
    "filteredData": "#valueOf($.some.complexArray)->#where(@x: @x.some.path < 10)",
    "projectedData": "#valueOf($.some.complexArray)->#select(@x: @x.some.path)"
}

source.json

{
    "some": {
        "integerArray": [ 1, 2, 6, 10 ],
        "complexArray": [
            { "some": { "path": 5 } },
            { "some": { "path": 30 } }
        ]
    }
}

output.json

{
    "hasValues": true,
    "filteredData": [
        { "some": { "path": 5 } }
    ],
    "projectedData": [ 5, 30 ]
}

Methods that take lambdas

Arity	Methods
One parameter	any, where, select, orderBy, orderByDesc, groupBy, summarizeWith, distinct, takeWhile, skipWhile, max, min, sum, average, try
Two parameters	reduce, zip

Your own C# methods can take lambdas too. See lambdas in external methods.