a!update

what do you wanna achieve ? Can you tell us more about your requirement

if you want to know how to use a!update function  refer to the below document.

https://docs.appian.com/suite/help/23.4/fnc_array_a_update.html, (Update function let's you update an array value at particular index you provide.)

Hi venky,

I want to promote only class 8 student  to 9

when I try below code it is updating all the students.

a!localVariables(
local!a: {
a!map(name: "X", class: 5, School: "ABC"),
a!map(name: "Y", class: 6, School: "ADC"),
a!map(name: "Z", class: 7, School: "AEC"),
a!map(name: "K", class: 8, School: "AFC")
},
a!forEach(
items: local!a,
expression: a!update(
data: fv!item,
index: "class",
value: 9
)
)

)

Thanks in Advance

  a!update(local!X[4],"class",9)

In case you don't know the index, just add the value you want to update in the where contains and it should work. 

a!update(
    data: local!var[wherecontains(8,local!var.class)],
    index: "class",
    value: 9
  )

Yeah it will update all , Cause you are iterating &  updating each individual . you are calling Update function 4 times, If you want to use for each I made small change to your code look into it.

a!localVariables(
  local!X:{
    a!map(name: "X", class: 5, School: "ABC"),
    a!map(name: "Y", class: 6, School: "ADC"),
    a!map(name: "Z", class: 7, School: "AEC"),
    a!map(name: "K", class: 8, School: "AFC")
  },
a!forEach(
  items: local!X,
  expression: 
  if(
    fv!item.class=8,
    a!update(fv!item,"class",9),
    fv!item
  )
)
)

Yeah it will update all , Cause you are iterating &  updating each individual . you are calling Update function 4 times, If you want to use for each I made small change to your code look into it.

a!localVariables(
  local!X:{
    a!map(name: "X", class: 5, School: "ABC"),
    a!map(name: "Y", class: 6, School: "ADC"),
    a!map(name: "Z", class: 7, School: "AEC"),
    a!map(name: "K", class: 8, School: "AFC")
  },
a!forEach(
  items: local!X,
  expression: 
  if(
    fv!item.class=8,
    a!update(fv!item,"class",9),
    fv!item
  )
)
)