Creating functions in an Acrobat form that were in the original excel file

Here you'll find some good info about mathematical functions available in JS:
http://w3schools.com/jsref/jsref_obj_math.asp

To calculate the average you can use a script like this (let's say you have 30 fields and the sum is saved in a field called "130SUM"):
Your other question, about counting the number of fields that have values in them is more complex.
Basically, it all depends on how you named your fields. If they are named consistently, like "Field1" to "Field360", then it becomes easier. In that case you can use something like this:

This will be the custom calculation code of your counting field.

PS - you should be aware that in Acrobat the field calculation order is not set automatically, like in Excel, so you have to make sure that it's set correctly (for example, that the average field is calculated after the total field).
You can edit it via Forms - Edit Forms - Set Field Calculation Order...

hi,

If fields are named using the Adobe form field naming convention it should be easier :

- fields must be named as "amount.0", "amount.1", "amount.2", and so on.
This can be done automaticaly using "Place Multiple fields" (Right-clic upon any form field with the Select Object Tool: http://help.adobe.com/en_US/acrobat/pro/using/WS8C2DDC1C-C174-4ad1-893F-B14A1C0289B4.php )

- then, in the "SUM" field you simply have to select the average (or the sum, etc.) of the (virtual) field "amount" available in the form field list.

This cause the SUM field to add all values caming from field named "amount.x".

See that screenshot: http://pix.am/ccb0/

;-)

How do you want to count and sum your fields?

Do you want to include null or empty fields?

Do you want to include zero value fields?

There is the feature to not only pick the fields to sum, but you can also average them if you want a null or empty field to be included as one of the fields with a value of zero.

If you want to exclude null or empty fields, not zero values, you will need to write a special function to skip the empty fields from the count of the fields.

There are a number of on demand videos and articles on this site that discuss forms, calculations, and JavaScript.

You might even consider using the OpenOffice.org suite, as the Write program can create form fields and export them to PDF.

If you use hierarchical field names:

// variable name for top most hierarchical field
var cTopName = "Text";

// sum hierarchical fields
function SumHfield(cTopName) {
// get top field object
var oFields = this.getField(cTopName);
// convert to an array
var aFields = oFields.getArray();
// variable for sum
var nSum = 0;
// sum field values for members of array
for ( i = 0; i < aFields.length; i++) {
nSum += Number(aFields[i].value);
}
return nSum;
}

// count the hierarchical fields
function CountHfield(cTopName) {
// get top field object
var oFields = this.getField(cTopName);
// convert to an array
var aFields = oFields.getArray();
// variable for count
var nCount = 0;
// sum field values for members of array
for ( i = 0; i < aFields.length; i++) {
// add test for null adjustment if needed
nCount++;
}
return nCount;
}

// average the hierarchical fields using the sum and count functions
function AvgHfield(cTopName) {
// variable for average
var nAvg = 0;
// variable for the count of fields
var nCount = CountHfield(cTopName);
if(nCount != 0) {
nAvg = SumHfield(cTopName) / nCount;
}
return nAvg;
}

// set the field value using the functions
event.value = AvgHfield(cTopName);

The above code will also automatically adjust for added or deleted fields as long as the hierarchical name structure is maintained.

If you place the functions at the document level, you only need to call the AvgHfield function with the appropriate field name to obtain the average of the fields.

FormCalc in LiveCycle Designer has functions that can dynamically sum, and count fields with the same name.