How can the numbers in the yaml field be automatically summed and updated automatically?

[tyf2018]

[blacksmithgu]

If you're willing to use a bit of DataviewJS:

`$= dv.span(dv.pages().amount.reduce((p, c) => p + c))`

[tyf2018]

😊👏Thanks！

[pmorberg]

I have the same situation; trying to sum a number however i get a TypeError when using this code:

$= dv.span(dv.pages().OtTime.reduce((p, c) => p + c))

This is the errormsg:
Dataview (for inline JS query 'dv.span(dv.pages().OtTime.reduce((p, c) => p + c))'): TypeError: dv.pages(...).OtTime.reduce is not a function

My attribute/yml-key is called OtTime. I have no .js exp but have tried to find solutions online without success. What could i be doing wrong?

[pmorberg]

So figured it out:

dv.span(dv.pages().OtTime.array().reduce((a, b) => a + b))

The array() and ,0 were needed. So just posting it if someone else are having the same probs.

[johngage]

So that would be: dv.span(dv.pages().OtTime.array().reduce((a, b) => a + b),0), correct? I don't yet know JS, so I do what you do.

I've been trying to understand how to use "sum" in dataview queries, and to understand the elegant solutions of SkepticMystic, mnvwvnm, blacksmithgu, and others.

I do wish someone would post a simple overall summary of how these arrays and lists work: how to deal with the arrays that dataview creates. It took me quite a while to realize that you had to GROUP BY something like "file.link" or "True" to generate rows, and that once you had rows, then you could use dot notation to retrieve field values, instead of "this.field". But I still can't figure out how to sum across rows. I've tried the "[0]" and "[0][0]" notation, I can see the field values, but I can't sum them.

In my case, I've been trying to build inventories of houses, and I have counts of water heaters, refrigerators, dishwashers, etc. in the YAML for the page for each house. I want a dataview table to add them up, across all houses. But it doesn't seem possible.

If I can get JS that works, I will try to shift to dynamically getting field count values from a separate pages for each water heater or appliance. I will link the house page to those water heater pages, and use the [[]].field reference to add them all up, allowing me to remove the static values from the house YAML. I hope.

Translating your answer to my field names works for dataviewjs; I get an accurate sum of the field values by having JS create an array of the field values. I'd hoped to do this in dataview, but it doesn't seem to work.

Now, how to build a table? It seems that once I'm in dataviewjs, there is no going back to a dataview query.
I have a copy and paste and modify JS table but can't figure out how to add in the dv.span value above.

---------Trial dataviwjs JS to make table----------It works, but how to insert the new summed value? ----

// Render a simple table of waterheater info sorted by address. 
let sum_wh 
sum_wh= dv.span(dv.pages("#WH").WH_count.array().reduce((p, c) => p + c),0)
dv.table(["File", "address", "owner", "WH_count", "sum_wh"],
  dv.pages("#WH")
   .sort(b => b.address) 
   .map(b => [b.file.link, b.address, b.energy, b.WH_count, sum_wh]))

Here my lack of JS expertise....where can sum_wh go so it's displayed? If I put it in the .map list, 
it returns the tantalizing value <Promise>

---------------------

Here's how the value of "sum_wh" works for adding up across all my waterheater pages by pulling values from the waterheater YAML:

dv.span(dv.pages("#WH").WH_count.array().reduce((p, c) => p + c),0)

This finds the tag values for the waterheater pages, finds the field that counts my waterheaters, and adds them across an array of their values. It works on YAML that looks like this:

-----Water Heater YAML-------
address: 2581
tags: WH, water, thermal_load
WH: True
WH_count: 1
exists: True
energy: gas
location: interior
make-model: ""
SN: 
tank: True
tank_size:
replace: True
heatpump-exists: False
heatpump-required: True

Is there any simple way to build a table in the same way for today's YAML for the house, YAML that has fields with counts, that looks like this?

----------------House YAML----
tags: HH, BSA, owner, HH/wh, HH/range
address: 3024
building: 1
owner: Owner
tenants: []
appliances:
- gas-range: 1
- electric-range: 0
- refrigerator: 1
- dishwasher: 1
- rangehood: 1
- ventilation-fan: 1
- washing-machine: 1
- dryer: 1
- microwave: 1
heat-pump:
- hp-hvac: 0
- hp-water: 0
furnace:
- gas: 1
- electric: 0
water-heater:
- gas: 1
- electric: 0
pv:
- panels: 0
- inverter: 0
- meter: 0
-------------------

Later, I want to replace this static YAML with links from each house page to the separate waterheater page for each address, hoping to use the link to get the count values dynamically from the waterheater pages....so I only update changes in one place, and can get rid of the static house page YAML counts.

Thank you for posting this.

[pmorberg]

Hi, sorry but only googling my wait out stuff here, no actual .js knowledge:-). Have you looked at the templater plugin? That has lots of dynamic field capabilities. I might not understand your problem correctly, though. I use textexpander to generate the relevant template for my .md docs, and make alterations to the static YAML as required. But i have nowhere near as many parameters as you.

[johngage]

Thank you for your response.
Yes, I have been trying to find a templater write-up that demonstrates those dynamic capabilities. I can now write templater templates, and invoke them by clicking on the left column templater icon. But I can't yet figure out how to invoke templater dynamically.
I'll keep trying.

[johngage]

And i have accumulated a set of inline dataview queries to sum the number of pages that satisfy a condition. Chaining requests requires a mental model of the sequence of arrays being generated by each element of the chain.
All queries use the length of the array as the sum. Getting into the JS world of reduce is a completely different level. mnvwvnm has elegant examples, as does tzhou. I'm thinking of building a web site filled with their solutions.
$= dv.pages('"EcoBlock/Equipment"').length counting all the pages in a folder.
$= dv.pages('"EcoBlock/Equipment"' && '#gas').length. adding pages with a tag
$=dv.pages('"EcoBlock/Equipment/Range"' && '#gas').where(p => p.location == "kitchen").length, extending that to add a WHERE condition
How many tags in vault: $=dv.pages().tags.length. counting tags
$= dv.pages('"EcoBlock/Households"').where(p => p.Status == "surveyed" && p["date-visited"] >= moment('2022-01-01') && p["date-visited"] <= moment('2022-12-31')).length. finding and counting pages in a date range