Summing up values in jinja2 - jinja2

Question

What would be the right way of getting the sum of the value in details.sections.details filtered by another attribute which would be the the value in name, i.e.: Earnings / Deduction?
Given the data:
{
"details":{
"totalPay":482.66,
"currency":"OMR",
"contributions":48.24,
"sections":[
{
"name":"Earnings",
"value":519.41,
"details":[
{
"name":"Overtime",
"value":60,
"notes":"Border OT",
"currency":"OMR"
},
{
"name":"H R A",
"value":96,
"notes":"",
"currency":"OMR"
},
{
"name":"LIVING ALLOWANCE",
"value":32,
"notes":"",
"currency":"OMR"
},
{
"name":"T A",
"value":32,
"notes":"",
"currency":"OMR"
},
{
"name":"Basic salary",
"value":299.408,
"notes":"",
"currency":"OMR"
}
]
},
{
"name":"Deductions",
"value":36.75,
"details":[
{
"name":"PASI - Employee (7%) - Employee",
"value":32.1586,
"notes":null,
"currency":"OMR"
},
{
"name":"Social Security Recovery (1%) - Employee",
"value":4.5941,
"notes":null,
"currency":"OMR"
}
]
}
]
}
}
I would expect to get, for Earnings:
60 + 96 + 32 + 32 + 299.408 = 519.408
and, for the Deductions:
32.1586 + 4.5941 = 36.7527
I will then dispalay the summed up values in a table.
I tried
{% set sum = details.sections.details|sum(attribute='value') -%}
But, the script does not load and I think there is an error in it.
I am able to get the individual values by looping.
I have declared a variable:
{% set sumAdditions = 0 %}
{% sumAdditions = sumAdditions + details.value %}
but this seems to fails as the script errors out.

Answer 1

details.sections is a list, so you either have to filter the list for earnings and deductions:
{% set earnings = (
details.sections | selectattr('name', 'eq', 'Earnings') | first
).details | sum(attribute='value')
%}
{% set deductions = (
details.sections | selectattr('name', 'eq', 'Deductions') | first
).details | sum(attribute='value')
%}
Or do it dynamically in a loop:
{% set sums = {} %}
{% for section in details.sections %}
{% do sums.update({
section.name: section.details | sum(attribute='value')
})
%}
{% endfor %}
Where sums will now contain a dictionary:
{'Earnings': 519.408, 'Deductions': 36.7527}
If, for some reason the {% do %} construct is not available for you, you can use a dummy set, so assign the return of the dictionary update to a variable you won't use:
{% set sums = {} %}
{% for section in details.sections %}
{% set dummy = sums.update({
section.name: section.details | sum(attribute='value')
})
%}
{% endfor %}