Python3 matplotlib script that plots histograms with data from text files (one number per line)

plot-histograms.py

#!/usr/bin/python3
"""
usage: {} title data.txt [data2.txt ...] > histogram.png
"""

import sys
import math
import os.path
import matplotlib
matplotlib.use('Agg')
import matplotlib.pyplot as plt  # noqa: F401

# display help if bad arguments
if len(sys.argv) < 3:
    print(__doc__.format(sys.argv[0]))
    sys.exit(1)


n = len(sys.argv) - 2
m = math.ceil(math.sqrt(n))
plotsize = (m, math.ceil(n / m))

fig = plt.figure(figsize=(4 * plotsize[1], 2.5 * plotsize[0]))
tle = fig.suptitle(sys.argv[1], fontsize=18, x=0.001, y=0.999,
                   horizontalalignment='left', verticalalignment='top',
                   bbox=dict(facecolor='none', edgecolor='black', pad=2))
plt.rcParams["axes.grid"] = True
plt.rcParams["grid.linestyle"] = "dotted"

maxylim = None
axislist = []

for i, filename in enumerate(sys.argv[2:]):
    pos = (i // plotsize[1], i % plotsize[1])
    axis = plt.subplot2grid(plotsize, pos)
    plt.title(os.path.basename(filename).split('.', 2)[0])

    with open(filename, 'r') as f:
        values = [float(l.strip()) for l in f.readlines()]

    su = sum(values)
    mean = round(su / len(values), 3)
    med = round(sorted(values)[len(values)//2], 3)
    su = round(su, 2)
    plt.xlabel("Values  [mean:{},med:{},sum:{}]".format(mean, med, su))
    plt.ylabel("Count  [total:{}]".format(len(values)))
    ys, xs, _ = plt.hist(values)  # , normed=True)

    for j, y in enumerate(ys):
        plt.text(xs[j], ys[j], str(int(ys[j])))

    if maxylim is None or axis.get_ylim() > maxylim:
        maxylim = axis.get_ylim()
    axislist.append(axis)

for axis in axislist:
    axis.set_ylim(maxylim)

plt.tight_layout()
plt.savefig(sys.stdout.buffer, format="png")
plt.close()