I have a following code:

       InputField[Dynamic[coefA], Number, ImageSize-> 130]
       (*InputField[Dynamic[SetPrecision[coefA,3]], Number, ImageSize->130]*), 
       Slider[Dynamic[coefA], {-10., 10., .01}, ImageSize -> 130]
    {{coefA, 0}, ControlType -> None}, 
    AppearanceElements -> None]

I want both Slider and InputField to be able to modify coefA variable, however I would like to have a special formatting inside InputField - to 2 decimal points (like: 1.2358->1.24). The commented line works... for the Slider. It can modify variable and it is printed correctly, but I loose ability to modify it via InputField because:

"Tag SetPrecision in SetPrecision[-1.74,3] is Protected."

Any ideas how it can be done?

  • 1
    $\begingroup$ Is this enough? Dynamic[SetPrecision[coefA, 3], (coefA = #) &] $\endgroup$
    – Kuba
    Dec 18, 2015 at 12:22
  • $\begingroup$ This is closely related topic: 6259 but solutions from there are not working with Number type InputField. $\endgroup$
    – Kuba
    Dec 18, 2015 at 12:26
  • $\begingroup$ I've noticed that you haven't accepted any of answers to you questions. Are they missing something. Please, take a tour. $\endgroup$
    – Kuba
    Jan 7, 2016 at 9:56
  • $\begingroup$ Oh I'm sorry i totally forgot I asked this question here! You suggested the same solution as my teacher so i totally forgot to thank you - Thanks, @Kuba. Im gonna mark this as '[SOLVED]' now (how to do so...? :D) $\endgroup$
    – michelson
    Jan 7, 2016 at 14:39
  • $\begingroup$ No worries, I just wanted to tell you about the accept mark because sometimes users are not aware of it. $\endgroup$
    – Kuba
    Jan 7, 2016 at 14:41

1 Answer 1


So, you can use very general answer from Michael E2 (the bottom of his answer) or this quick fix:

    InputField[Dynamic[SetPrecision[coefA, 3], (coefA = #) &], Number], 
    Slider[Dynamic[coefA], {-10., 10., .01}]

Keep in mind that precision is not closely related to number of digits after decimal point.

To have 10.12 and 1.23 at once you have to use NumberForm[var, {Infinity, 2}] and approach from linked answer.


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