I have a value like "A1~B2~C3" in a multiple PV. Now I want to convert

Ah that's why, you are using an older version. The split function is designed to work with single valued text inputs, in newer versions that is not a problem but in yours you won't be able to use multi-valued strings with the split() functions which kind of makes sense since the purpose is to convert a text into an array therefore passing an array of text doesn't match the arguments of the function (although is handled correctly in newer versions)

Since you are in an old version of Appian you should try using the DoForEach plug-in. It has been deprecated but most likely you already have it in your environment, that way you can call this rule for each item in the array; you will pass the array to the doForEach while the rule that runs the split will be receiving a single item (the string to be converted to an array).

Ah that's why, you are using an older version. The split function is designed to work with single valued text inputs, in newer versions that is not a problem but in yours you won't be able to use multi-valued strings with the split() functions which kind of makes sense since the purpose is to convert a text into an array therefore passing an array of text doesn't match the arguments of the function (although is handled correctly in newer versions)

Since you are in an old version of Appian you should try using the DoForEach plug-in. It has been deprecated but most likely you already have it in your environment, that way you can call this rule for each item in the array; you will pass the array to the doForEach while the rule that runs the split will be receiving a single item (the string to be converted to an array).