The extract function extracts a substring from string, part of number from a number and range of elements from an array.

Syntax

output = extract(expression, range)

Inputs

expression : a reference to a variable or any [[expression|Expressions]]. range : denoted by x..y where x and y are optional and integers. Default value of x = 0 Default value of y = length of value of expression

Output

output : string, number or array depending on input.

Example flow

Schema dummy {
    string string1
    string nullstring
    number number1
    arrayinput [
        string key
    ]
    jsonObject {
      string jfield
    }
    boolean flag
  }

Schema dummyOutput {
  string result1
  string result2
  string result3
  string result4
  string result5
  string result6
  string result7
  string result8
  string result9
  string result10
  string result11
  string result12
  string result13
  string result14
  string result15
  string result16
  string result17
  number result18
  number result19
  number result20
  arrayoutput1 [
    string key
  ]
  arrayoutput2 [
    string key
  ]
  arrayoutput3 [
    string key
  ]
  arrayoutput4 [
    string key
  ]
  resultJsonObject {
    string jfield
  }
  string resultJson
  string resultflag
  string invalidRange1
}

value dummyValue1 -> dummy {
  "hello"
  ${null}
    675575757
    arrayinput [
        {
            "field1"
        }
        {
            "field2"    
        }
        {
            "field3"    
        }
        {
            "field4"    
        }
    ]
    jsonObject {
        "jsonField1"
    }
    true
}

Mapping dummyMapping input dummyValue1 as x output dummyOutput as op {
  op.result1 = extract(x.nullstring, 5..9)
  op.result2 = extract(x.nullstring, ..)
  op.result3 = extract(x.nullstring, 1..)
  op.result4 = extract(x.nullstring, ..4)

  op.result5 = extract(x.string1, 0..2)
  op.result6 = extract(x.string1, 5..9)
  op.result7 = extract(x.string1, 5..)
  op.result8 = extract(x.string1, 1..)
  op.result9 = extract(x.string1, 9..)
  op.result10 = extract(x.string1, ..2)
  op.result11 = extract(x.string1, ..5)
  op.result12 = extract(x.string1, ..)
  op.result13 = extract(x.string1, 0..0)
  op.result14 = extract(x.string1, 5..5)

  op.result15 = extract(x.number1, 5..9)
  op.result16 = extract(x.number1, 0..5)
  op.result17 = extract(x.number1, ..)
  op.result18 = extract(x.number1, ..5)
  op.result19 = extract(x.number1, 3..)
  op.result20 = extract(x.number1, 3..30)

  op.arrayoutput1 = extract(x.arrayinput, 1..2)
  op.arrayoutput2 = extract(x.arrayinput, ..3)
  op.arrayoutput3 = extract(x.arrayinput, 2..)
  op.arrayoutput4 = extract(x.arrayinput, ..)

  op.resultJsonObject = extract(x.jsonObject, ..)
  op.resultJson = extract(x.jsonObject, ..)

  op.resultflag = extract(x.flag, 1..2)

  op.invalidRange1 = extract(x.string1, hivd..fwfwedsf)

}

Flow mappingFlow {
    Start dummyMapping {}
}

Output for Example Flow

{
  "result1": null,
  "result2": null,
  "result3": null,
  "result4": null,
  "result5": "he",
  "result6": null,
  "result7": "",
  "result8": "ello",
  "result9": null,
  "result10": "he",
  "result11": "hello",
  "result12": "hello",
  "result13": "hello",
  "result14": "",
  "result15": "5757",
  "result16": "67557",
  "result17": "675575757",
  "result18": 67557,
  "result19": 575757,
  "result20": null,
  "arrayoutput1": [
    {
      "key": "field2"
    }
  ],
  "arrayoutput2": [
    {
      "key": "field1"
    },
    {
      "key": "field2"
    },
    {
      "key": "field3"
    }
  ],
  "arrayoutput3": [
    {
      "key": "field3"
    },
    {
      "key": "field4"
    }
  ],
  "arrayoutput4": [
    {
      "key": "field1"
    },
    {
      "key": "field2"
    },
    {
      "key": "field3"
    },
    {
      "key": "field4"
    }
  ],
  "resultJsonObject": {
    "jfield": null
  },
  "resultJson": null,
  "resultflag": null,
  "invalidRange1": "hello"
  }