How to push individual (optional) parameters into an array - arrays

Question

I'm trying to populate an array (fruit.Price)with properties supplied in the first WITH line of the following cypher code:
WITH [{Price_1:15,Price_2:20,Price_3:17,strFruit:"apples"},{Price_1:2,Price_2:1,Price_3:1.5,Price_4:3,strFruit:"pears"}] AS props
UNWIND props as p
MATCH (fruit:Fruit) WHERE fruit.strFruit=p.strFruit
FOREACH (price in [p.Price_1,p.Price_2,p.Price_3,p.Price_4] |SET fruit.Price = fruit.Price + price)
RETURN fruit
where the maximum quantity of p.Price_n is 4, but not all are necessarily supplied (as above, where p.Price_4 is missing in the first row). These properties will always be supplied consecutively i.e. Price_4 won't be supplied without Price_3 also.
How do I populate an array with a variable number of elements in this way? For what it's worth; I'm actually using the HTTP Rest API and the WITH line is in reality a parameters: command.
thanks

Answer 1

I would use coalesce(), and default to 0 for the ones that don't exist. Also, it might be easier to do reduce() instead of foreach(). (Updated to use CASE/WHEN instead of coalesce.)
Even easier would be to pass in an array of variable length {prices:[15,20,17], strFruit:"apples"}... or just the total price (if you have control over that).
WITH [{Price_1:15,Price_2:20,Price_3:17,strFruit:"apples"},{Price_1:2,Price_2:1,Price_3:1.5,Price_4:3,strFruit:"pears"}] AS props
UNWIND props as p
MATCH (fruit:Fruit) WHERE fruit.strFruit=p.strFruit
SET fruit.Price = reduce(total = [], price in [p.Price_1,p.Price_2,p.Price_3,p.Price_4] | CASE WHEN NOT price is NULL THEN total + price ELSE total END)
RETURN fruit
http://console.neo4j.org/r/o69bii