Sum of values in array of objects without reduce function

[Tanmay_Sarkar]

Hello all,

I stumbled upon a situation where I have to find out a sum of a certain key in the objects residing in an array without reducing the objects? What I mean to say is, here is the input:

[
{
key1: value1,
key2: 10
},
{
key1: value2,
key2: 20
},
{
key1: value3,
key2: 30
}
]

The output that I am expecting should look like:

[
{
key1: value1,
key2: 10,
sum: 60
},
{
key1: value2,
key2: 20,
sum: 60
},
{
key1: value3,
key2: 30,
sum: 60
}
]

The total sum of key 2 values should be pushed into each object as a new key.

Can some one please suggest how to deal with this? Reducing won’t be the optimal solution as it would discard the objects and just add a new object with the total sum.

Thanks.

[bojanvelevski]

Hi @Tanmay_Sarkar,

You can also use Apache Velocity within JSON Generator. Here is the script:

---

#set($sum = 0)
#foreach ($field in $group)
#set($sum=$sum+$field.key2)
#end

#foreach($field in $group)
#set($dummy = $field.put(“sum”,$sum))
#end

{“group”:$group}

---

Regards,
Bojan

[Tanmay_Sarkar]

@bojanvelevski Thanks a lot, I never realized Apache Velocity can be used within JSON generator in such a way, this would come in handy in future.

[Tanmay_Sarkar]

@skatpally Thanks a lot, this worked effortlessly.