Hi Paul, > The reason you were getting that error is because unless you > specify otherwise, ax.bar will make the bottom of the bars at 0 - > which isn't an allowed date, hence the error. Change your bar > line to this (I also added align='center', but you can remove it > if you want):
Aha, OK that makes sense. Thank you. I think the point #3 in my previous email about the "Ordinal must be >= 1" has all been about what is or isn't allowed as a proper date. So your example worked of course, but I am still not able to get my real code to plot a bar chart. If I tell you what the format of the data is, maybe you can help me. I would like to plot dates (on x axis) versus time intervals (on y). I have a list of dates and I have a two lists (self.data[0] and self.data[1]), one of the start times ("bots") and one of the stop times ("tops"). But when I go to plot it, and do this (based on your code...for now leaving out the round() step): bots = self.data[0] tops = self.data[1] bars = self.subplot.bar(self.final_dates, top-bot, bottom=bot, align='center') I get the error: TypeError: unsupported operand type(s) for -: 'list' and 'list' Because I am trying to subtract the "bots" list from the "tops" list. In the example code I gave, bot and times were not lists but were a 'numpy.ndarray' and a numpy.float64' object, respectfully, and I guess the - operand can be used on them. How can I structure my data such that this can work? (For some reason I have not had nearly this much confusion with plotting lines, just bars). Thanks for all the help, Che (CM) ------------------------------------------------------------------------------ Special Offer-- Download ArcSight Logger for FREE (a $49 USD value)! Finally, a world-class log management solution at an even better price-free! Download using promo code Free_Logger_4_Dev2Dev. Offer expires February 28th, so secure your free ArcSight Logger TODAY! http://p.sf.net/sfu/arcsight-sfd2d _______________________________________________ Matplotlib-users mailing list Matplotlib-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/matplotlib-users