### Sudoku constraints

Developing a constraint formula to identify naked sets During the development of the sudoku solver it occurred to me that there had to be a better way to look for naked sets than to try a pair, then […]

### The birthday problem

This problem is often used to show that statistics are sometimes counter intuitive.  If you try to imagine how many people you would need to have a 50% chance of two people sharing the same birthday, you’d […]

### Leveraging sorted data with Match

What can you learn here? Optimization and profiling filling ranges using VBA using match to partition data Another approach to Array formulas and large Ranges I previously covered a VBA solution for a problem that could […]

### Optimizing the array formula

What can you learn here? Optimization and profiling Filling ranges using VBA Array formulas I previously covered a VBA solution for a problem that could have been solved using array formulas.  However, it really wasn’t the best […]

### Array formulas and large ranges

What can you learn here? array formulas VBA using VBA profiler using worksheet profiler Are Array formulas viable with large ranges On the Excel Blackbelts forum, someone asked a very interesting question about how to analyze relationships between […]

### Bit Twiddling

What is bit twiddling Sometimes you need to do many logical operations at once. For example, consider the problem where you want to find which numbers exist in both of two strings, which are stored […]

### Array formulas and sumproduct

Using array formulas rather than sumproduct We looked at the use of sumproduct() previously. Lets repeat that using array formulas instead. Array formulas will give you more solution options than sumproduct() can – anyway you will see that sumproduct() is just a special case of an […]

### Array Formulas Introduction

These are a much overlooked feature of Excel, largely because array functions can be hard to understand. The power of many regular formulas such as countif, sumif that you use every day can be increased […]

### Array formulas – doing lots of things at once

Many  people have a love hate relationship with what is perhaps Excel’s most powerful capability. Normally you don’t use them enough to become completely comfortable with them, but when you do you wish you had […]