HP Prime and where is undo? (1062 Views)
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Frequent Advisor
davetheguru
Posts: 83
Registered: ‎11-20-2013
Message 1 of 7 (1,062 Views)

HP Prime and where is undo?

I use 'undo' on my HP-50g often for a mistaken operation on my RPN stack.

 

I have not seen this ability really on the Prime.  Sure I could just press the reset button and let the reboot put me back where I was (assuming that was right after I powered up).  Not a 'pure' method.

 

Also, when I'm editing a note, spreadsheet, etc., I run into the same problem -- oops, I didn't mean to delete all that, where is the control-Z key?

 

If there is not an undo on the Prime, it is yet another one of my suggestions.

 

Occasional Visitor
eiskreis
Posts: 2
Registered: ‎03-05-2014
Message 2 of 7 (849 Views)

Re: HP Prime and where is undo?

The same issue I have found.  If someone from HP could write anything about this...

Occasional Visitor
eiskreis
Posts: 2
Registered: ‎03-05-2014
Message 3 of 7 (837 Views)

Re: HP Prime and where is undo?

 

No one in english has answered this post.. even  "auf deutsch" there is a lot of answers, why not in english...Take a look at:

 

 

http://h30492.www3.hp.com/t5/Weitere-HP-Endverbraucherprodukte-und-technologien/HP-Prime-Bugs/td-p/1...

Trusted Contributor
cyrille
Posts: 78
Registered: ‎11-18-2004
Message 4 of 7 (825 Views)

Re: HP Prime and where is undo?

Hello,

 

Sorry, we have not implemented undo in HP Prime.

 

Cyrille

Collector
Dante_cs
Posts: 2
Registered: ‎11-21-2013
Message 5 of 7 (784 Views)

Re: HP Prime and where is undo?

I know that the "UNDO" key is already imposible to implement from the actual phisical achitecture of the HP Prime, but how about on the next "HP Prime II"? please don't forget about this missing key!

Occasional Visitor
JoseNunes
Posts: 1
Registered: ‎10-15-2014
Message 6 of 7 (272 Views)

Re: HP Prime and where is undo?

As a suggestion : there is an app for iPhone ( Pcalc42 ) where to undo , simply slide your finger up the screen to the left , and redo , slides to the right.

It would be fantastic in the HP Prime!

 

Greetings!

Trusted Contributor
Joseph Horn
Posts: 100
Registered: ‎09-25-2006
Message 7 of 7 (249 Views)

Re: HP Prime and where is undo?

Don't forget about [Shift] [+] which sort of "undoes" the most recent RPN calculation, by pushing its arguments onto the stack.  It's the same as LASTARG on the RPL models (HP 28/48/49/50).  Ignore the fact that it's labeled "Ans" on the keyboard.  In does NOT return the most recent Answer; it returns the most recent INPUTS to a function.

 

Example: 1 Enter 2 + Ans --> 3, 1, 2 on the stack (the result and the inputs).

 

This is very handy, and not only when you want to UNDO an operation. For example, what's the resistance of a 6 ohm and 10 ohm resistor connected in parallel?  The usual way to calculate this is 1/(1/A+1/B) which in Prime RPN can be done this way:

 

6 [X^-1] 10 [X^-1] [+] [X^-1] --> 3.75 ohms

 

But it's also equal to (A*B)/(A+B) which in Prime RPN can be done this way:

 

6 10 [×] [Ans] [+] [÷] --> 3.75 ohms

-Joe-
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