.. _pylab_examples-log_demo: pylab_examples example code: log_demo.py ======================================== .. plot:: /home/tcaswell/src/p/matplotlib/doc/mpl_examples/pylab_examples/log_demo.py :: import numpy as np import matplotlib.pyplot as plt plt.subplots_adjust(hspace=0.4) t = np.arange(0.01, 20.0, 0.01) # log y axis plt.subplot(221) plt.semilogy(t, np.exp(-t/5.0)) plt.title('semilogy') plt.grid(True) # log x axis plt.subplot(222) plt.semilogx(t, np.sin(2*np.pi*t)) plt.title('semilogx') plt.grid(True) # log x and y axis plt.subplot(223) plt.loglog(t, 20*np.exp(-t/10.0), basex=2) plt.grid(True) plt.title('loglog base 2 on x') # with errorbars: clip non-positive values ax = plt.subplot(224) ax.set_xscale("log", nonposx='clip') ax.set_yscale("log", nonposy='clip') x = 10.0**np.linspace(0.0, 2.0, 20) y = x**2.0 plt.errorbar(x, y, xerr=0.1*x, yerr=5.0 + 0.75*y) ax.set_ylim(ymin=0.1) ax.set_title('Errorbars go negative') plt.show() Keywords: python, matplotlib, pylab, example, codex (see :ref:`how-to-search-examples`)