Show decimal places and scientific notation on the axis of a matplotlib plot

This is really easy to do if you use the matplotlib.ticker.FormatStrFormatter as opposed to the LogFormatter. The following code will label everything with the format '%.2e':

import numpy as npimport matplotlib.pyplot as pltimport matplotlib.ticker as mtickfig = plt.figure()ax = fig.add_subplot(111)x = np.linspace(0, 300, 20)y = np.linspace(0,300, 20)y = y*1e16ax.plot(x,y)ax.yaxis.set_major_formatter(mtick.FormatStrFormatter('%.2e'))plt.show()

In order to get nicely formatted labels in scientific notation one may use the formatting capabilities of a ScalarFormatter which uses MathText (Latex) and apply it to the labels.

import matplotlib.pyplot as pltimport numpy as npimport matplotlib.ticker as mtickerfig, ax = plt.subplots()x = np.linspace(0, 300, 20)y = np.linspace(0,300, 20)y = y*1e16ax.plot(x,y)f = mticker.ScalarFormatter(useOffset=False, useMathText=True)g = lambda x,pos : "${}$".format(f._formatSciNotation('%1.10e' % x))plt.gca().yaxis.set_major_formatter(mticker.FuncFormatter(g))plt.show()

While this may be useful in a lot of cases, it does not actually meet the requirements of the question. To have equal digits on all labels a more customized version can be used.

import matplotlib.pyplot as pltimport numpy as npimport matplotlib.ticker as mtickerfig, ax = plt.subplots()x = np.linspace(0, 300, 20)y = np.linspace(0,300, 20)y = y*1e16ax.plot(x,y)class MathTextSciFormatter(mticker.Formatter):    def __init__(self, fmt="%1.2e"):        self.fmt = fmt    def __call__(self, x, pos=None):        s = self.fmt % x        decimal_point = '.'        positive_sign = '+'        tup = s.split('e')        significand = tup[0].rstrip(decimal_point)        sign = tup[1][0].replace(positive_sign, '')        exponent = tup[1][1:].lstrip('0')        if exponent:            exponent = '10^{%s%s}' % (sign, exponent)        if significand and exponent:            s =  r'%s{\times}%s' % (significand, exponent)        else:            s =  r'%s%s' % (significand, exponent)        return "${}$".format(s)# Format with 2 decimal placesplt.gca().yaxis.set_major_formatter(MathTextSciFormatter("%1.2e"))plt.show()