Posts about LAMBDA.
REDUCE is the most powerful of the functional array functions and the most overlooked. The lambda which means you can accumulate strings, and replace calculations that used to need VBA.
Joining a column of names or tags into one comma-separated string used to need TEXTJOIN or a helper column. REDUCE does it in one formula, and lets you transform each item before it gets concatenated.
LAMBDA, MAP, REDUCE, SCAN, BYROW. These are functional programming primitives. Excel is shipping them one by one, and most users are still writing nested IFs. The spreadsheet you learned in 2015 has been quietly replaced by something much more powerful.
You'll build a dropdown list that reads from a structured table and includes every new row automatically. No named range maintenance, no 'why isn't my new entry showing up' moments. Structured table plus a spill reference, and your validation list never needs touching again.
MAP takes your LAMBDA and runs it on every element in an array. No helper columns, no dragging formulas, no VBA loops. It's the Excel equivalent of a functional programming pattern, and once you've used it, going back to column-by-column formulas feels like a step backwards.
You'll build a summary that calculates a custom metric for every row in your dataset without a pivot table, without helper columns, and without copying formulas down. BYROW plus a LAMBDA gives you …
BYROW hands your function an entire row at a time. BYCOL does the same by column. Together they replace an entire category of 'drag this formula down and keep it updated' work — and when you combin…
XLOOKUP, LET, LAMBDA, BYROW, SCAN, MAP — Microsoft shipped more genuinely useful functions in the last three years than in the previous decade. If you learned Excel before 2022 and haven't revisite…
BYROW hands your function an entire row at a time — which means 'apply this logic to every row in this range' is one formula in one cell. No dragging, no CTRL+SHIFT+ENTER, no missing the last row w…
Helper columns aren't wrong. But when a running total requires three of them and breaks every time someone inserts a row, you've created fragility in exchange for familiarity. The Excel array funct…
Running totals used to mean helper columns or array gymnastics. SCAN changes that — it applies a function cumulatively across an array and hands you back every intermediate result. Once you see it …
SCAN hands you every intermediate result as it accumulates — which means a running total is one formula that spills down the column. No helper rows, no dragging, no breaking when someone inserts a …
The counter-argument to 'if your formula needs a scrollbar to read, it's wrong.' With LAMBDA, complexity lives in one named place and gets called cleanly everywhere else. The formula in your cell c…
You'll build a named LAMBDA called OVERDUE that takes a date and a threshold and returns a clean status label. Then you'll call it in three different tables in the same workbook. By the end, you'll…
Before LAMBDA, every Excel function that existed was one Microsoft decided to write. After LAMBDA, you can write them yourself — naming the logic, hiding the complexity, and calling your custom fun…
One function definition in the Name Manager, and every cell in the workbook can call it like a built-in. LAMBDA + named functions means you stop copy-pasting logic and start writing like someone wh…