reject( predicate, list, context )
Calls a predicate for each item in a list, rejects any items for which the returned value is true, and returns all remaining items.
Keyword | Type | Description |
---|---|---|
|
Function, Rule, or Data Type Constructor |
Expression that returns a Boolean (true or false). |
|
Any Type Array |
List of elements that the predicate iterates through. |
|
Any Type Array |
Variable number of parameters passed directly into each function evaluation. |
Any Type Array
Use fn!functionName
or a!functionName
to reference an expression function and rule!ruleName
to reference a rule.
To use rules or functions that take more than two arguments, use the merge() function. For example, given a rule g(x, y, z)
, reduce(rule!g, i, merge({a, b, c}, {d, e, f}))
returns g(g(g(i, a, d), b, e), c, f)
.
a!forEach()
cannot be used within rules used in this function.
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reject(
a!isNullOrEmpty,
{1, 2, null, 3, null, 4}
)
Returns {1, 2, 3, 4}
.
To help demonstrate how the context parameter works in looping expressions, let's look at an example.
Imagine you're building an expression that uses looping to analyze group membership in your application. You have four Group constants configured in the following ways:
Constant | Group(s) referenced | Group membership |
---|---|---|
cons!csaAdmins | CSA Administrators | user1, user3 |
cons!csaProfs | CSA Professors | user1, user2, user4, user5, user6, user7 |
cons!csaBuilding1 | CSA Building 1 | user1, user2, user3, user5, user6, user7 |
cons!allGroups | CSA Adminstrators, CSA Professors, CSA Building 1 | See above |
The following SAIL expressions reference these constants to show how context works when checking items in a list.
Note: You'll need to adapt these expression examples for your own purposes, since the examples reference constants that may not exist in your Appian environment.
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reject(
a!isUserMemberOfGroup,
{"user1", "user2", "user3"},
cons!csaAdmins
)
Returns {"user2"}
when user1 and user3 are members of the group referenced by cons!csaAdmins
. a!isUserMemberOfGroup
has 3 parameters: username, groups, and matchAllGroups. The reject()
list corresponds to username, and the list of values provided in the context parameter are used as the next two parameters, groups & matchAllGroups.
Learn more about a!isUserMemberOfGroup().
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reject(
a!isUserMemberOfGroup,
{"user1", "user2", "user3"},
{cons!allGroups, true}
)
Returns {"user2", "user3"}
when only user1 is a member of all the groups referenced in cons!allGroups
. a!isUserMemberOfGroup
has 3 parameters: username, groups, and matchAllGroups. The reject()
list corresponds to username, and the list of values provided in the context parameter are used as the next two parameters, groups & matchAllGroups.
Learn more about a!isUserMemberOfGroup().
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reject(
a!isUserMemberOfGroup,
{"user1", "user2", "user3"},
merge({cons!csaAdmins, cons!csaProfs}, {true, true})
)
Returns {"user2", "user3"}
. In this case, only user1 is a member of the groups referenced in cons!csaAdmins
and cons!csaProfs
. The merge() function maps the list values to the correct parameters in this example.
Learn more about a!isUserMemberOfGroup().
In this example, we will use a helper rule, rule!isDateLater(value, referenceDate)
, which is defined as:
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ri!value > ri!referenceDate
Example filter:
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reject(
rule!isDateLater,
{date(1950, 2, 3), date(1950, 6, 23), date(1950, 5, 2)},
date(1950, 4, 7)
)
Returns {2/3/1950}
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 | Incompatible | Cannot be used to configure a process report. |
Process Events | Incompatible | Cannot be used to configure a process event node, such as a start event or timer event. |
reject() Function