barchart_demo.py

# -*- coding: utf-8 -*-
# https://matplotlib.org/3.2.1/gallery/statistics/barchart_demo.html

import sys
from collections import namedtuple

import numpy as np
from matplotlib.backends.backend_qt5agg import FigureCanvas
from matplotlib.figure import Figure
from matplotlib.ticker import MaxNLocator
from PyQt5.QtWidgets import QApplication

app = QApplication(sys.argv)

fig = Figure(figsize=(9, 7))
canvas = FigureCanvas(fig)
canvas.resize(640, 480)
canvas.show()

np.random.seed(42)

Student = namedtuple("Student", ["name", "grade", "gender"])
Score = namedtuple("Score", ["score", "percentile"])

# GLOBAL CONSTANTS
test_names = ["Pacer Test", "Flexed Arm\n Hang", "Mile Run", "Agility", "Push Ups"]
test_meta = dict(zip(test_names, ["laps", "sec", "min:sec", "sec", ""]))


def attach_ordinal(num):
    """Convert an integer to an ordinal string, e.g. 2 -> '2nd'."""
    suffixes = {
        str(i): v
        for i, v in enumerate(
            ["th", "st", "nd", "rd", "th", "th", "th", "th", "th", "th"]
        )
    }

    v = str(num)
    # special case early teens
    if v in {"11", "12", "13"}:
        return v + "th"
    return v + suffixes[v[-1]]


def format_score(scr, test):
    """
    Build up the score labels for the right Y-axis by first
    appending a carriage return to each string and then tacking on
    the appropriate meta information (i.e., 'laps' vs. 'seconds'). We
    want the labels centered on the ticks, so if there is no meta
    info (like for pushups) then don't add the carriage return to
    the string
    """
    md = test_meta[test]
    if md:
        return "{}\n{}".format(scr, md)
    else:
        return scr


def format_ycursor(y):
    y = int(y)
    if y < 0 or y >= len(test_names):
        return ""
    else:
        return test_names[y]


def plot_student_results(student, scores, cohort_size):
    #  create the figure
    ax1 = fig.subplots()
    fig.subplots_adjust(left=0.115, right=0.88)
    fig.canvas.set_window_title("Eldorado K-8 Fitness Chart")

    pos = np.arange(len(test_names))

    rects = ax1.barh(
        pos,
        [scores[k].percentile for k in test_names],
        align="center",
        height=0.5,
        tick_label=test_names,
    )

    ax1.set_title(student.name)

    ax1.set_xlim([0, 100])
    ax1.xaxis.set_major_locator(MaxNLocator(11))
    ax1.xaxis.grid(True, linestyle="--", which="major", color="grey", alpha=0.25)

    # Plot a solid vertical gridline to highlight the median position
    ax1.axvline(50, color="grey", alpha=0.25)

    # Set the right-hand Y-axis ticks and labels
    ax2 = ax1.twinx()

    scoreLabels = [format_score(scores[k].score, k) for k in test_names]

    # set the tick locations
    ax2.set_yticks(pos)
    # make sure that the limits are set equally on both yaxis so the
    # ticks line up
    ax2.set_ylim(ax1.get_ylim())

    # set the tick labels
    ax2.set_yticklabels(scoreLabels)

    ax2.set_ylabel("Test Scores")

    xlabel = (
        "Percentile Ranking Across {grade} Grade {gender}s\n"
        "Cohort Size: {cohort_size}"
    )
    ax1.set_xlabel(
        xlabel.format(
            grade=attach_ordinal(student.grade),
            gender=student.gender.title(),
            cohort_size=cohort_size,
        )
    )

    rect_labels = []
    # Lastly, write in the ranking inside each bar to aid in interpretation
    for rect in rects:
        # Rectangle widths are already integer-valued but are floating
        # type, so it helps to remove the trailing decimal point and 0 by
        # converting width to int type
        width = int(rect.get_width())

        rankStr = attach_ordinal(width)
        # The bars aren't wide enough to print the ranking inside
        if width < 40:
            # Shift the text to the right side of the right edge
            xloc = 5
            # Black against white background
            clr = "black"
            align = "left"
        else:
            # Shift the text to the left side of the right edge
            xloc = -5
            # White on magenta
            clr = "white"
            align = "right"

        # Center the text vertically in the bar
        yloc = rect.get_y() + rect.get_height() / 2
        label = ax1.annotate(
            rankStr,
            xy=(width, yloc),
            xytext=(xloc, 0),
            textcoords="offset points",
            ha=align,
            va="center",
            color=clr,
            weight="bold",
            clip_on=True,
        )
        rect_labels.append(label)

    # make the interactive mouse over give the bar title
    ax2.fmt_ydata = format_ycursor
    # return all of the artists created
    return {
        "fig": fig,
        "ax": ax1,
        "ax_right": ax2,
        "bars": rects,
        "perc_labels": rect_labels,
    }


student = Student("Johnny Doe", 2, "boy")
scores = dict(
    zip(
        test_names,
        (
            Score(v, p)
            for v, p in zip(
                ["7", "48", "12:52", "17", "14"],
                np.round(np.random.uniform(0, 100, len(test_names)), 0),
            )
        ),
    )
)
cohort_size = 62  # The number of other 2nd grade boys

arts = plot_student_results(student, scores, cohort_size)

sys.exit(app.exec_())