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how should a program ask for no SI prefix?
11-24-2015, 03:14 PM
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how should a program ask for no SI prefix?
With SI written units, the absence of an SI prefix is indicated by a null: as in "m" instead of "mm".

I may have missed it (I have only looked at free specs) but I have not seen an equivalent that would suit a program.

If I have a pop-up selector (CHOOSE or INPUT) prompting for K,M,G,... how should I signify " no prefix"? Which will probably be the default.
The problem with "no prefix" is:
- its longer than K, so might not fit your form
- it needs translation
- The opposite of "no prefix" is "a prefix", not a specific one.

Using a null entry (equivalent to the written " m" for metres) is inconvenient, particularly on the HP Prime: There is no clue that this is your prefix input rather than something else, and HP Prime's default prompt is for a value - the inexperienced user is likely to try to type in a number rather than select a choice.

For mathematical users one might avoid translation by using a number but even this can be confusing. Should one specify " 1" as in multiply by 1,1000,1000000? Or should one specify ^0 as in 1e6,1e3,1e0? Of course either could be used - but are there any hints as to what works and what doesn't? Does the SI organisation have any recommendations? (And if not, why not?)

Stephen Lewkowicz (G1CMZ)
ANDROID HP Prime App broken offline on some mobiles
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how should a program ask for no SI prefix? - StephenG1CMZ - 11-24-2015 03:14 PM

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