◆ MATLAB

Count elements of a given value in a matrix

This is real work, not a feature someone invented — it comes from real job ads and real questions people asked. Below are four ready AI prompts: get it done, make it easy for the next person to say yes to, work out the right move when you are stuck, and stop it coming back.

4prompts

The same task, four prompts

today's deadline · the next reviewer · the stuck moment · the pattern
AExecute — do the immediate taskI need to count how many times the value 7 appears in the 'sensor_data' matrix and store that…+
I need to count how many times the value 7 appears in the 'sensor_data' matrix and store that count in a variable called 'seven_count'.
when the reply comes backPush once: ask it to sharpen the weakest part, and to say what it assumed. Helpful?
BImprove — make it easier to acceptBefore I run this analysis on the new batch of sensor readings, make sure the count of 'NaN'…+
Before I run this analysis on the new batch of sensor readings, make sure the count of 'NaN' values is also tracked, as those indicate faulty sensors. Also, if the count of 7s or NaNs exceeds 10% of the total elements, flag that as a potential issue.
when the reply comes backPush once: ask it to sharpen the weakest part, and to say what it assumed. Helpful?
CDecide — diagnose the stuck momentThe simulation just finished, and the output is way off. I suspect there might be a lot of zero…+
The last simulation run gave unexpected results, and I'm not sure if it's the data or the algorithm.
The simulation just finished, and the output is way off. I suspect there might be a lot of zero values in the 'input_matrix' that are skewing the calculations, but I can't just filter them out without understanding why they're there. If it's a data generation bug, I need to tell Dr. Evans before Friday. What's the fastest way to check the prevalence and distribution of zeros without altering the original data, and what's the most likely reason for this kind of discrepancy?
when the reply comes backPush once: ask it to sharpen the weakest part, and to say what it assumed. Helpful?
DBecome — change the patternI'm constantly wasting hours trying to find why my calculations are wrong, only to discover a…+
I keep losing time debugging when my matrices have unexpected values.
I'm constantly wasting hours trying to find why my calculations are wrong, only to discover a matrix is full of 'NaN's or 'Inf's from an earlier step. This happens almost every other week. What habit should I change to automatically check for these problematic values after every major processing step, so I catch them before they propagate and corrupt my final results?
when the reply comes backPush once: ask it to sharpen the weakest part, and to say what it assumed. Helpful?

Questions people actually ask

honest answers, no sign-up

Every task here was seen in the real world. Someone doing the job named it, a real job ad asked for it, or a lot of people asked about it online.

If nothing real showed a task, it is not on the page. That is the whole rule.

They are the same job approached four ways, because what you need depends on where you are.

Get it done today. Make it easy for the next person to say yes to. Work out the right move when you are stuck. Learn the pattern so the job stops coming back.

For most of these jobs it can carry the heavy thinking - draft it, sort it, check it, rehearse it with you.

It cannot sit in your chair, take the blame when a number is wrong, or notice what nobody wrote down. Let it do the first 80%. Keep the last 20% that is truly yours.

No. Copy any prompt and paste it into the AI you already use. No account, no score, no wall in the way.

Any of them. The prompts describe the work rather than naming a product, so they are not tied to one assistant.

That is also why they keep working when you switch.

Change it freely. Every prompt is a starting line, not a rule.

Put in your real numbers, your real names and your real deadline. The more you make it yours, the better the answer comes back.

The tasks come from real job ads, published job data and the questions people ask in public forums.

The steps come from MATLAB's own documentation, with practitioner sources for the traps the manual does not mention.

Push once. Ask it to sharpen the weakest part and to say what it assumed.

Most wrong answers come from a missing detail rather than a bad prompt - tell it the thing it could not know.