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In this article
BYROW runs a LAMBDA on each row of an array and returns one result per row — row totals, row maximums, row checks.
Syntax
=BYROW(array, LAMBDA(row, calculation))| Argument | What it means |
|---|---|
LAMBDA(row, …) |
What to do with each row. |
Examples
Example 1
=BYROW(B2:M20, LAMBDA(r, SUM(r)))Yearly total for every product.
Example 2
=BYROW(B2:M20, LAMBDA(r, COUNTIF(r, 0)))Months with zero sales per product.
BYROW in practice
Where you will use it
- Row totals or flags in one spilled formula
- Max per row without helper columns
- Row-level checks on dynamic data
Worked example
| Data rows | Formula | Result |
|---|---|---|
| 2 | =ARRAYTOTEXT(BYROW(TAKE({10,20,30;5,15,25;1,2,3},A2),LAMBDA(r,MAX(r)))) | 30, 25 |
| 3 | =ARRAYTOTEXT(BYROW(TAKE({10,20,30;5,15,25;1,2,3},A3),LAMBDA(r,MAX(r)))) | 30, 25, 3 |
| 1 | =ARRAYTOTEXT(BYROW(TAKE({10,20,30;5,15,25;1,2,3},A4),LAMBDA(r,MAX(r)))) | 30 |
Results calculated in Excel.
Mistakes people make
| Mistake | What to do instead |
|---|---|
| Returning arrays per row | #CALC!; return a single value |
| Performance | Fine for thousands of rows, slower for very large data |
Related functions
BYCOL · LAMBDA · MAP
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📎 Practice files for this article
- 📗Practice workbook: Logic, LET & LAMBDA17 tasks on realistic sales data — type your formula, the Check column turns green when it is right. Answers sheet included.⬇ XLSX · 35 KB
Free to use for learning. Files with macros (.bas) are plain text — import them with Alt+F11 → File → Import File, and always test on a copy.
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