reduce Operator (Examples): 티들리위키 — 줄 없는 개인 웹 공책

reduce Operator (Examples)

2020년 12월 4일 오후 1:11

These examples use the following predefined variables:

add-price: [get[price]multiply{!!quantity}add<accumulator>]
num-items: [get[quantity]add<accumulator>]
join-with-commas: [<index>compare:number:gt[0]then<accumulator>addsuffix[, ]addsuffix<currentTiddler>else<currentTiddler>]
multiply-input: [multiply<accumulator>]

They also use the following data tiddlers:

[tag[shopping]reduce<num-items>]

[tag[shopping]reduce<add-price>]

[tag[shopping]reduce<join-with-commas>]

→ Uses <index> to act differently on the first item than the rest

[tag[non-existent]reduce<add-price>]

→ Empty input produces empty output

[tag[non-existent]reduce<add-price>else[0]]

→ Use else to ensure output if input was empty

=1 =2 =3 +[reduce<multiply-input>]

→ Empty initial value is treated as 0 by mathematical operators

=1 =2 =3 +[reduce<multiply-input>,[1]]

→ Setting initial value is sometimes necessary for correct results