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REDUCE
REDUCE processes an array element by element, maintaining a running accumulator value that is updated by a LAMBDA function at each step, and returns the final accumulated result. It is used to compute custom aggregations — such as products, string joins, or running totals — that cannot be expressed with standard aggregate functions.
Excel
=REDUCE(0,A2:A5,LAMBDA(acc,x,acc+x))Google Sheets
=REDUCE(0,A2:A5,LAMBDA(acc,x,acc+x))Try it with your data
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How it works
- 1Choose an initial accumulator value — 0 for sums, 1 for products, or an empty string for text concatenation.
- 2Enter =REDUCE(0,A2:A5,LAMBDA(acc,x,acc+x)) to sum all values in A2:A5 starting from 0.
- 3Change the LAMBDA body for different aggregations: LAMBDA(acc,x,acc*x) gives the product; LAMBDA(acc,x,acc&", "&x) concatenates with commas.
Need a version for your data?
Try: “Compute the running product of all values in a range using a custom accumulator”