I want to plot a series of values against a date range in matplotlib. I changed the tick base parameter to 7, to get one tick at the beginning of every week (plticker.IndexLocator, base = 7). The problem is that the set_xticklabels function does not accept a base parameter. As a result, the second tick (representing day 8 on the beginning of week 2) is labelled with day 2 from my date range list, and not with day 8 as it should be (see picture).
How to give set_xticklabelsa base parameter?
Here is the code:
my_data = pd.read_csv("%r_filename_%s_%s_%d_%d.csv" % (num1, num2, num3, num4, num5), dayfirst=True)
my_data.plot(ax=ax1, color='r', lw=2.)
loc = plticker.IndexLocator(base=7, offset = 0) # this locator puts ticks at regular intervals
ax1.set_xticklabels(my_data.Date, rotation=45, rotation_mode='anchor', ha='right') # this defines the tick labels
ax1.xaxis.set_major_locator(loc)
Here is the plot:
Many thanks - your solution perfectly works. For the case that other people run into the same issue in the future: i have implemented the above-mentioned solution but also added some code so that the tick labels keep the desired rotation and also align (with their left end) to the respective tick. May not be pythonic, may not be best-practice, but it works
x_fmt = mpl.ticker.IndexFormatter(x)
ax.set_xticklabels(my_data.Date, rotation=-45)
ax.tick_params(axis='x', pad=10)
ax.xaxis.set_major_formatter(x_fmt)
labels = my_data.Date
for tick in ax.xaxis.get_majorticklabels():
tick.set_horizontalalignment("left")