It's pretty common to have bar charts where the x axis is a set of string labels rather than numbers. This can currently be done in pyplot with e.g.

bar([1,2,3],[4,3,6], align='center')
gca().xaxis.set_ticks([1, 2, 3])
gca().xaxis.set_ticklabels(['one', 'two', 'three'])

but it would be much nicer to simply support

bar(['one', 'two', 'three'], [4,3,6])

Similarly for barh and possibly some other plot types.

cc: @alanedelman