| """ |
| =================================== |
| Percentiles as horizontal bar chart |
| =================================== |
| |
| Bar charts are useful for visualizing counts, or summary statistics |
| with error bars. Also see the :doc:`/gallery/lines_bars_and_markers/barchart` |
| or the :doc:`/gallery/lines_bars_and_markers/barh` example for simpler versions |
| of those features. |
| |
| This example comes from an application in which grade school gym |
| teachers wanted to be able to show parents how their child did across |
| a handful of fitness tests, and importantly, relative to how other |
| children did. To extract the plotting code for demo purposes, we'll |
| just make up some data for little Johnny Doe. |
| """ |
|
|
| from collections import namedtuple |
|
|
| import matplotlib.pyplot as plt |
| import numpy as np |
|
|
| Student = namedtuple('Student', ['name', 'grade', 'gender']) |
| Score = namedtuple('Score', ['value', 'unit', 'percentile']) |
|
|
|
|
| def to_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) |
| |
| if v in {'11', '12', '13'}: |
| return v + 'th' |
| return v + suffixes[v[-1]] |
|
|
|
|
| def format_score(score): |
| """ |
| Create score labels for the right y-axis as the test name followed by the |
| measurement unit (if any), split over two lines. |
| """ |
| return f'{score.value}\n{score.unit}' if score.unit else str(score.value) |
|
|
|
|
| def plot_student_results(student, scores_by_test, cohort_size): |
| fig, ax1 = plt.subplots(figsize=(9, 7), layout='constrained') |
| fig.canvas.manager.set_window_title('Eldorado K-8 Fitness Chart') |
|
|
| ax1.set_title(student.name) |
| ax1.set_xlabel( |
| 'Percentile Ranking Across {grade} Grade {gender}s\n' |
| 'Cohort Size: {cohort_size}'.format( |
| grade=to_ordinal(student.grade), |
| gender=student.gender.title(), |
| cohort_size=cohort_size)) |
|
|
| test_names = list(scores_by_test.keys()) |
| percentiles = [score.percentile for score in scores_by_test.values()] |
|
|
| rects = ax1.barh(test_names, percentiles, align='center', height=0.5) |
| |
| |
| large_percentiles = [to_ordinal(p) if p > 40 else '' for p in percentiles] |
| small_percentiles = [to_ordinal(p) if p <= 40 else '' for p in percentiles] |
| ax1.bar_label(rects, small_percentiles, |
| padding=5, color='black', fontweight='bold') |
| ax1.bar_label(rects, large_percentiles, |
| padding=-32, color='white', fontweight='bold') |
|
|
| ax1.set_xlim([0, 100]) |
| ax1.set_xticks([0, 10, 20, 30, 40, 50, 60, 70, 80, 90, 100]) |
| ax1.xaxis.grid(True, linestyle='--', which='major', |
| color='grey', alpha=.25) |
| ax1.axvline(50, color='grey', alpha=0.25) |
|
|
| |
| ax2 = ax1.twinx() |
| |
| ax2.set_ylim(ax1.get_ylim()) |
| |
| ax2.set_yticks( |
| np.arange(len(scores_by_test)), |
| labels=[format_score(score) for score in scores_by_test.values()]) |
|
|
| ax2.set_ylabel('Test Scores') |
|
|
|
|
| student = Student(name='Johnny Doe', grade=2, gender='Boy') |
| scores_by_test = { |
| 'Pacer Test': Score(7, 'laps', percentile=37), |
| 'Flexed Arm\n Hang': Score(48, 'sec', percentile=95), |
| 'Mile Run': Score('12:52', 'min:sec', percentile=73), |
| 'Agility': Score(17, 'sec', percentile=60), |
| 'Push Ups': Score(14, '', percentile=16), |
| } |
|
|
| plot_student_results(student, scores_by_test, cohort_size=62) |
| plt.show() |
|
|
| |
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|
