I have array input like below in a intermediate AWS Step function state and I want to join that into a single string, I know States.StringSplit for splitting string with separator into array, does reverse of it possible with Intrinsic functions without writing a lambda function?
e.g: Input parameters as:
{
"inputArray": ["a","b","c"],
"joiner": "/"
}
I am expecting below ResultPath:
{"joinedValue": "a/b/c/"}
Or
{"joinedValue": "a/b/c"}
You can do it with a step function and no lambdas, but it isn't one step - you need a loop that combines all the pieces into one string:
JoinArray:
id: JoinArrayStateMachine
name: ${self:service}-${self:provider.stage}-JoinArrayStateMachine
type: EXPRESS
definition:
Comment: Join Array Orchestration
Version: "1.0"
StartAt: Make Input
States:
Make Input:
Type: Pass
Parameters:
inputArray.$: States.StringSplit('a,b,c',',')
joiner: /
Next: Get First Item
Get First Item:
Type: Pass
Parameters:
index: 1
increment: 1
item.$: States.ArrayGetItem($.inputArray, 0)
length.$: States.ArrayLength($.inputArray)
ResultPath: $.iterator
Next: Check Joined Items Length
Check Joined Items Length:
Type: Choice
Choices:
- Variable: $.joinedValue
IsPresent: false
Next: Create Joined Items
- Variable: $.joinedValue
StringEquals: ''
Next: Create Joined Items
Default: Append Joined Items
Create Joined Items:
Type: Pass
Parameters:
iterator.$: $.iterator
inputArray.$: $.inputArray
joiner.$: $.joiner
joinedValue.$: $.iterator.item
Next: Check Index
Append Joined Items:
Type: Pass
Parameters:
iterator.$: $.iterator
inputArray.$: $.inputArray
joiner.$: $.joiner
joinedValue.$: States.Format('{}{}{}',$.joinedValue,$.joiner,$.iterator.item)
Next: Check Index
Check Index:
Type: Choice
Choices:
- Variable: $.iterator.length
NumericGreaterThanPath: $.iterator.index
Next: Get Next Item
Default: Finish
Get Next Item:
Type: Pass
Parameters:
index.$: States.MathAdd($.iterator.index, $.iterator.increment)
increment.$: $.iterator.increment
item.$: States.ArrayGetItem($.inputArray, $.iterator.index)
length.$: States.ArrayLength($.inputArray)
ResultPath: $.iterator
Next: Check Joined Items Length
Finish:
Type: Pass
Parameters:
iterator: ()
inputArray.$: $.inputArray
joiner.$: $.joiner
joinedValue.$: $.joinedValue
Next: End
End:
Type: Succeed
