There is a "noiytick" suboption for by() :
twoway scatter rep78 mpg, by(foreign, noiytick)
Another way, rather than reducing the length to zero, would be to remove the
color of the ticks:
twoway scatter rep78 mpg, ylabel(, tlcolor(none)) by(foreign)
Scott
> -----Original Message-----
> From: [email protected] [mailto:owner-
> [email protected]] On Behalf Of Nick Cox
> Sent: Sunday, December 11, 2005 2:21 PM
> To: [email protected]
> Subject: st: omitting ticks on -twoway- with -by()-
>
> Here is a tip I thought I would pass on. On a -twoway-
> plot, whenever an axis shows a categorical variable,
> I often want to suppress the ticks, which to me
> convey the impression of marks on a numerical scale.
> A simple example is
>
> sysuse auto, clear
> scatter rep78 mpg, by(foreign)
>
> If you want to suppress the ticks for -rep78-,
> then the mind springs towards
>
> scatter rep78 mpg, by(foreign) yla(, notick)
>
> but this does not do what you hope it will, as
> the -notick- has no effect.
>
> I owe to Vince Wiggins an assurance that there is
> a good explanation for this rooted in the way that
> graphs using -by()- are put together, although it is
> evidently too subtle to be easily explained.
>
> He patiently pointed out to me that working at the code
> to make this possible is hardly essential, given the
> possible work-around
>
> scatter rep78 mpg, by(foreign) yla(, tlength(0))
>
> which perhaps struck you immediately as the solution.
>
> There is no doubt some subtle quasi-philosophical
> distinction between no tick and a tick of zero length,
> but they look pretty similar to me.
>
> So that's it then: -tlength(0)- is a way to suppress
> ticks when more obvious methods fail.
>
> Nick
> [email protected]
>
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