Category Archives: arrays

Excel JavaScript API Part 4: The shallow copy problem

I was trying to read the values from a Range and then write modified versions of the values to two different ranges. Should be straightforward: Well this does not work: both B4 and B6 have 0.91 added to them: wrong … Continue reading

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Excel JavaScript API Part 3: Benchmark of Processing Arrays Performance – Loop vs Reduce vs COUNTIFS vs VBA

In a previous post I compared several different ways of processing data with VBA. The fastest way was to get the data into a variant array and loop on it. JavaScript has some powerful array methods so I wanted to … Continue reading

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Excel JavaScript API Part 2: Benchmark of Read/Write Range Performance

As an Excel Office Developer many of the Excel based applications I develop depend on reading data from Excel worksheet ranges, processing it and then writing the processed data back to a worksheet. In VBA the way to do this … Continue reading

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Writing Efficient VBA UDFs Part 14: Handling whole columns using Implicit Intersection – Updated

Excel has an interesting and very efficient trick called Implicit Intersection which allows you to use large Named Ranges and whole column references efficiently. What is Implicit Intersection? When Excel expects to get a single cell reference but you give … Continue reading

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Excel What-If Data Tables: Faster calculation with VBA

For some reason this year I keep on meeting Excel’s What-If Data Tables. These are used (often in real estate and financial valuation models) to simplify doing sensitivity analysis against a range of values for certain inputs such as interest … Continue reading

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Excel Full Column References and Used Range: Good Idea or Bad Idea?

Some people love using full column references such as A:A, other people say they slow down your workbook to a crawl and lead to workbook and memory bloat. The attraction of using whole column references is that you don’t have … Continue reading

Posted in arrays, Calculation, Formatting, Memory | 5 Comments

Writing Efficient VBA UDFs (Part13): MaxMinFair Resource Allocation – an array UDF example

Last year we got to spend a great day at Microsoft Research in Cambridge (UK). one presentation was about storage strategies and featured (amongst other stuff) an interesting algorithm called MaxMinFair. The MaxMinFair algorithm You can read about it here … Continue reading

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Stacking (Appending) Arrays/Ranges in Excel: Formulas versus Functions Shootout

This post is a follow up to my last post Using Constant Arrays and Expressions in Excel Formulas. I will explore how some of the general purpose array-handling functions in FastExcel SpeedTools Extras compare with formulas using native Excel functions. … Continue reading

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Using Constant Arrays and Array Expressions in Excel Formulas

How Excel handles array expressions and constants in single-cell and multi-cell formulas is not well documented. So here is my attempt to shed some light on the subject. What are Constant Arrays? Constant arrays are Excel formula expressions that allow … Continue reading

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