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axes.format_{x,y} data should have a setter #17286
Description
In the Date tick labels example, the code for setting the cursor coords message overwrites the default formatters:
ax.format_xdata = mdates.DateFormatter('%Y-%m-%d')
ax.format_ydata = lambda x: '$%1.2f' % x # format the price.This creates confusion because runs counter to how basically everything else in matplotlib is set via setter but especially the formatters:
ax.xaxis.set_major_formatter(mdates.DateFormatter('%Y'))and the docs aren't especially clear either on this being a property:
Axes.format_xdata(self, x)
Return x formatted as an x-value.
This function will use the fmt_xdata attribute if it is not None, else will fall back on the xaxis major formatter.
To be consistent with the API, I'm proposing properties/functions of the form:
ax.{x,y}data_formatter(mdates.DateFormatter('%Y-%m-%d'))ax.data_formatter(which=(x,y, both), mdates.DateFormatter('%Y-%m-%d'))
Activity
anntzer commentedon Apr 30, 2020
Really this should be called something like
set_xcursor_formatter,datais just too vague.story645 commentedon Apr 30, 2020
Agree, and should also steal from #16715 that it should take a str, callable, or mticker instance.
story645 commentedon May 4, 2020
And xref #9593 'cause fixing this issue should maybe help fix that one?
github-actions commentedon Mar 30, 2026
This issue has been marked "inactive" because it has been 365 days since the last comment. If this issue is still present in recent Matplotlib releases, or the feature request is still wanted, please leave a comment and this label will be removed. If there are no updates in another 30 days, this issue will be automatically closed, but you are free to re-open or create a new issue if needed. We value issue reports, and this procedure is meant to help us resurface and prioritize issues that have not been addressed yet, not make them disappear. Thanks for your help!