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if() Function

Function

if( condition, valueIfTrue, valueIfFalse )

Returns valueIfTrue if condition returns true; returns valueIfFalse otherwise.

See also:

  • a!match(): Allows specifying a series of condition pairs using equal and then, or whenTrue and then. Can often achieve more complex logic than if().
  • choose(): Returns a result based on the index provided. Can often result in similar logic to if() when paired with wherecontains().
  • a!defaultValue: Consider using the a!defaultValue function when you are replacing a null value with another value or have nested if and isnull statements.

Parameters

Keyword Type Description

condition

Boolean

A test that determines whether valueIfTrue or valueIfFalse will be returned.

valueIfTrue

Any Type

The value to be returned if condition returns true.

valueIfFalse

Any Type

The value to be returned if condition returns false.

Returns

Any Type

Usage considerations

Evaluation properties

  • Unlike most functions, if() does not always evaluate all of its parameters. When passed a single condition, the function evaluates the condition and then only the value parameter that is returned.
  • All parameters are required for the if() function.
  • The condition value is cast to a Boolean. If it fails to cast, the if() function returns an error.

Null and empty values

  • When null values are passed to the condition parameter, they are considered to be false.
  • When null values are passed to the valueIfTrue or valueIfFalse parameters, a null value is also returned for the corresponding true or false.

Lists of values

When a list is passed to the condition parameter, it is treated as a list of conditions, so the valueIfTrue and valueIfFalse parameters return lists of values. This means that when passed an empty list, if() always returns an empty list.

If the lists in the condition and value parameters are the same length, the index of each condition corresponds to the item selected for the result. For example:

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if(
  {true, false, true, false, true},
  {"One", "Two", "Three", "Four", "Five"},
  {"A", "B", "C", "D", "E"}
)

Returns {"One", "B", "Three", "D", "Five"}.

However, if the value parameters have shorter lists than the condition, the index is not maintained. Instead, each item is returned in order (and repeats if necessary). For example:

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if(
  {true, false, true, false, true, true, true},
  {"One", "Two", "Three", "Four"},
  {"A", "B", "C", "D"}
)

Returns {"One", "A", "Two", "B", "Three", "Four", "One"}.

When passed a list containing a single boolean and lists in the value parameters, only the first item of the selected list will be returned. However, if a single value is passed to the condition and there are lists in the value parameters, the entire list is returned.

Examples

Basic examples

if(null, 1, 0) returns 0

if(true, 1, error("Doesn't get evaluated")) returns 1 (because the parameter with error() does not get evaluated)

if(true, { 2, 4, 6 }, { 1, 3, 5 }) returns { 2, 4, 6 }

if({true, false, true}, { 2, 4, 6 }, { 1, 3, 5 }) returns { 2, 3, 6 }

if({true}, { 2, 4, 6 }, { 1, 3, 5 }) returns { 2 }

if({}, { 2, 4, 6}, { 1, 3, 5 }) returns {}

Evaluating only one output

if(true, 1, error("Doesn't get evaluated")) returns 1 (because the parameter with error() does not get evaluated)

Using if() to return a default result

The if() function is often used when calling an integration to handle cases where an integration failed or returned a null response.

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a!localVariables(
  local!result: rule!MY_Integration(),
  if(
    a!isNullOrEmpty(local!result),
    0,
    local!result.totalCount
  )
)

In this case, when the integration returns an empty result, a default count of 0 is returned. Otherwise, the total count from the result is used.

Using if() to determine whether to show a component as read only

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a!localVariables(
  local!isReadOnly: true,
  local!value,
  a!textField(
    label: "Text",
    labelPosition: if(
      local!isReadOnly,
      "JUSTIFIED",
      "ABOVE"
    ),
    readOnly: local!isReadOnly,
    required: if(
      local!isReadOnly,
      false,
      true
    ),
    saveInto: local!value,
    value: local!value,
  )
)

When the variable local!isReadOnly is changed, it determines the component's readOnly value, as well as additional display properties.

Feature compatibility

The table below lists this function's compatibility with various features in Appian.
Feature Compatibility Note
Portals Compatible
Offline Mobile Compatible
Sync-Time Custom Record Fields Compatible

Can be used to create a custom record field that only evaluates at sync time.

Real-Time Custom Record Fields Incompatible

Custom record fields that evaluate in real time must be configured using one or more Custom Field functions.

Process Reports Compatible
Process Events Compatible
Open in Github Built: Fri, Feb 23, 2024 (09:13:50 PM)

if() Function

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