Viz 4: Categorical Bar Plot Series

viz4_barplots.py

# Matplotlib version: 3.5.2 (My Local Jupyter Notebook)
# Seaborn version: 0.11.2 (My Local Jupyter Notebook)
# Python version: 3.7.4 (My Local Jupyter Notebook)

import pandas as pd
import matplotlib.pyplot as plt
import seaborn as sns
%matplotlib inline
sns.set(style="white",context="talk")

def cat_bar_plot(df,col_cat,col_y,suptitle, figsize=(14,6)):
    '''
    This helper function integrates boxplot, barchart, distribution-plot all together. 
    The plot_type parameter controls the output graph format.
    
    Input:
        df: pandas dataframe
        col_cat: string. the column name of the key categorical variable (key dimension).
        col_y: string. the column name of the dependent variable (key metric).
        figsize: tuple. The width and height of the figure.
    Output:
        fig: figure object.
    '''
    fig, axes = plt.subplots(nrows=1, ncols=2, figsize=figsize)
    sns.countplot(
        x=col_cat, 
        data=df,
        ax=axes[0],
        palette=sns.color_palette("summer_r",df[col_cat].nunique())
    )
    axes[0].set_title(f'Number of obs. by {col_cat}', fontsize=16, pad = 5)
    axes[0].grid(linestyle="--", alpha=0.4)

    sns.barplot(
        x=col_cat, 
        y=col_y, 
        data=df, 
        ci=0, 
        ax=axes[1],
        estimator = np.mean,
        palette=sns.color_palette("summer_r",df[col_cat].nunique())
    );
    axes[1].set_title(f'{col_y} by {col_cat}', fontsize = 16, pad = 5)
    axes[1].grid(linestyle="--", alpha=0.4)

    fig.suptitle(suptitle, fontsize = 20)
    plt.show()
    
    return fig

# ====================================================================================
# Illustration
# Load the data
tips = sns.load_dataset("tips")
tips['tip_perc']=tips.tip/tips.total_bill

fig = cat_bar_plot(
    df = tips,
    col_cat = 'sex',
    col_y = 'tip_perc',
    suptitle = "Examining Tipping Percentage Difference between Male and Female Customers"
)

fig.savefig(
    fname = "../categorical_bar_plot_series.png", # path&filename for the output
    dsi = 300, # make it a high-resolution graph
    bbox_inches='tight' # sometimes default savefig method cuts off the x-axis and x-ticks. This param avoids that 
)