Note
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Tick formatters#
Tick formatters define how the numeric value associated with a tick on an axisis formatted as a string.
This example illustrates the usage and effect of the most common formatters.
The tick format is configured via the functionset_major_formatterorset_minor_formatter. It accepts:
a format string, which implicitly creates a
StrMethodFormatter.a function, implicitly creates a
FuncFormatter.an instance of a
Formattersubclass. The most common areNullFormatter: No labels on the ticks.StrMethodFormatter: Use stringstr.formatmethod.FormatStrFormatter: Use %-style formatting.FuncFormatter: Define labels through a function.FixedFormatter: Set the label strings explicitly.ScalarFormatter: Default formatter for scalars: auto-pick the format string.PercentFormatter: Format labels as a percentage.
SeeTick formatting for a complete list.
importmatplotlib.pyplotaspltfrommatplotlibimporttickerdefsetup(ax,title):"""Set up common parameters for the Axes in the example."""# only show the bottom spineax.yaxis.set_major_locator(ticker.NullLocator())ax.spines[['left','right','top']].set_visible(False)# define tick positionsax.xaxis.set_major_locator(ticker.MultipleLocator(1.00))ax.xaxis.set_minor_locator(ticker.MultipleLocator(0.25))ax.xaxis.set_ticks_position('bottom')ax.tick_params(which='major',width=1.00,length=5)ax.tick_params(which='minor',width=0.75,length=2.5,labelsize=10)ax.set_xlim(0,5)ax.set_ylim(0,1)ax.text(0.0,0.2,title,transform=ax.transAxes,fontsize=14,fontname='Monospace',color='tab:blue')fig=plt.figure(figsize=(8,8),layout='constrained')fig0,fig1,fig2=fig.subfigures(3,height_ratios=[1.5,1.5,7.5])fig0.suptitle('String Formatting',fontsize=16,x=0,ha='left')ax0=fig0.subplots()setup(ax0,title="'{x} km'")ax0.xaxis.set_major_formatter('{x} km')fig1.suptitle('Function Formatting',fontsize=16,x=0,ha='left')ax1=fig1.subplots()setup(ax1,title="def(x, pos): return str(x-5)")ax1.xaxis.set_major_formatter(lambdax,pos:str(x-5))fig2.suptitle('Formatter Object Formatting',fontsize=16,x=0,ha='left')axs2=fig2.subplots(7,1)setup(axs2[0],title="NullFormatter()")axs2[0].xaxis.set_major_formatter(ticker.NullFormatter())setup(axs2[1],title="StrMethodFormatter('{x:.3f}')")axs2[1].xaxis.set_major_formatter(ticker.StrMethodFormatter("{x:.3f}"))setup(axs2[2],title="FormatStrFormatter('#%d')")axs2[2].xaxis.set_major_formatter(ticker.FormatStrFormatter("#%d"))deffmt_two_digits(x,pos):returnf'[{x:.2f}]'setup(axs2[3],title='FuncFormatter("[{:.2f}]".format)')axs2[3].xaxis.set_major_formatter(ticker.FuncFormatter(fmt_two_digits))setup(axs2[4],title="FixedFormatter(['A', 'B', 'C', 'D', 'E', 'F'])")# FixedFormatter should only be used together with FixedLocator.# Otherwise, one cannot be sure where the labels will end up.positions=[0,1,2,3,4,5]labels=['A','B','C','D','E','F']axs2[4].xaxis.set_major_locator(ticker.FixedLocator(positions))axs2[4].xaxis.set_major_formatter(ticker.FixedFormatter(labels))setup(axs2[5],title="ScalarFormatter()")axs2[5].xaxis.set_major_formatter(ticker.ScalarFormatter(useMathText=True))setup(axs2[6],title="PercentFormatter(xmax=5)")axs2[6].xaxis.set_major_formatter(ticker.PercentFormatter(xmax=5))plt.show()
Total running time of the script: (0 minutes 1.734 seconds)