Repository: matplotlib/matplotlib
File: galleries/examples/lines_bars_and_markers/hat_graph.py (Python)

Code before:
def hat_graph(ax, xlabels, values, group_labels):
    """
    Create a hat graph.

    Parameters
    ----------
    ax : matplotlib.axes.Axes
        The Axes to plot into.
    xlabels : list of str
        The category names to be displayed on the x-axis.
    values : (M, N) array-like
        The data values.
        Rows are the groups (len(group_labels) == M).
        Columns are the categories (len(xlabels) == N).
    group_labels : list of str
        The group labels displayed in the legend.
    """

    values = np.asarray(values)
    x = np.arange(values.shape[1])
    ax.set_xticks(x, labels=xlabels)
    heights0 = values[0]

    # Draw the hats
    bars = ax.grouped_bar(
        (values - heights0).T, bottom=heights0, tick_labels=xlabels,
        labels=group_labels, edgecolor='black', group_spacing=0.8)

    # Attach a text label on top of each bar
    for bc, heights in zip(bars.bar_containers, values):
        ax.bar_label(bc, heights, padding=4)

    # Remove the color that would otherwise show in the first group's legend entry
    bars.bar_containers[0].patches[0].set_facecolor('none')


# Initialise labels and a numpy array make sure you have
# N labels of N number of values in the array
xlabels = ['I', 'II', 'III', 'IV', 'V']
playerA = np.array([5, 15, 22, 20, 25])
playerB = np.array([25, 32, 34, 30, 27])

fig, ax = plt.subplots(layout='constrained')

hat_graph(ax, xlabels, [playerA, playerB], ['Player A', 'Player B'])

# Add some text for labels, title and custom x-axis tick labels, etc.
ax.set_xlabel('Games')
ax.set_ylabel('Score')
ax.set_ylim(0, 60)
ax.set_title('Scores by number of game and players')

Review comment (suggestion):
Slight preference to inline `heights0 = values[0]`. I think that extra variable made sense when we had `heights` in the for loop, but now only introduces additional mental load without any benefit.

```suggestion
        (values - values[0]).T, bottom=values[0], tick_labels=xlabels,
```

Code after:
def hat_graph(ax, xlabels, values, group_labels):
    """
    Create a hat graph.

    Parameters
    ----------
    ax : matplotlib.axes.Axes
        The Axes to plot into.
    xlabels : list of str
        The category names to be displayed on the x-axis.
    values : (M, N) array-like
        The data values.
        Rows are the groups (len(group_labels) == M).
        Columns are the categories (len(xlabels) == N).
    group_labels : list of str
        The group labels displayed in the legend.
    """

    values = np.asarray(values)
    color_cycle_colors = plt.rcParams['axes.prop_cycle'].by_key()['color']

    # Draw the hats
    bars = ax.grouped_bar(
        (values - values[0]).T, bottom=values[0], tick_labels=xlabels,
        labels=group_labels, edgecolor='black', group_spacing=0.8,
        colors=['none'] + color_cycle_colors)

    # Attach a text label on top of each bar
    for bc, heights in zip(bars.bar_containers, values):
        ax.bar_label(bc, heights, padding=4)


# Initialise labels and a numpy array make sure you have
# N labels of N number of values in the array
xlabels = ['I', 'II', 'III', 'IV', 'V']
playerA = np.array([5, 15, 22, 20, 25])
playerB = np.array([25, 32, 34, 30, 27])

fig, ax = plt.subplots(layout='constrained')

hat_graph(ax, xlabels, [playerA, playerB], ['Player A', 'Player B'])

# Add some text for labels, title and custom x-axis tick labels, etc.
ax.set_xlabel('Games')
ax.set_ylabel('Score')
ax.set_ylim(0, 60)
ax.set_title('Scores by number of game and players')
ax.legend()

plt.show()
# %%