Sorry, I've tried, it display strange things.
PS1='%# %(#,$,%%)'

2011/12/7 Jos Backus <jos@catnook.com>

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>
> On Tue, Dec 6, 2011 at 8:43 PM, Geoff Wing <gcw@zsh.org> wrote:
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>> Please CC replies to Daniel.
>>
>> ----- Forwarded message from Daniel Lin <dlin.tw@gmail.com> -----
>>
>> I'm trying to move from bash to zsh.
>> I found a problem.  My 'expect' scripts require a '$' sign to let me know
>> its done.
>>
>> In zsh the %# will display % when user's effective id is not 0.
>> But, I require another similar function which display '$' instead of '%'.
>>
>> Could you consider to add this function to help bash users' life easier?
>>
>> I already change my PS1="\\$"
>> But its function is not equal to %#.
>>
>> ----- End forwarded message -----
>>
>
> How about using `%(,,)'?
>
> Example prompt string:
>
> %m:%~%# %(#,$,%%)
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> --
> Jos Backus
> jos at catnook.com
>