A connected scatterplot is useful to display the evolution of 2 variables. The following graph demonstrates the evolution of baby names Amanda and Ashley in years. It shows the number of babies named Amanda in the x axis and Ashley in the y axis. Note that, pandas pivot_table() function is used to prepare the data structure and matplotlib plot() function is used to plot a connected scatterplot. You can also add text labels and arrows to the plot.
# Import packages
import pandas as pd
import matplotlib.pyplot as plt
# import dataset
df = pd.read_csv("https://raw.githubusercontent.com/holtzy/data_to_viz/master/Example_dataset/5_OneCatSevNumOrdered.csv")
# filter data
df = df.loc[(df.name=="Ashley") | (df.name=="Amanda")]
df = df.loc[(df.sex=="F") & (df.year>1970)]
df = pd.pivot_table(df, values='n', index=['year'], columns=['name'])
# set the figure size
plt.figure(figsize=(10, 10))
# plot the connected scatterplot
plt.plot(df.Amanda, df.Ashley, '-', marker='o')
# add annotations in every 3 data points with a loop
for line in range(0, df.shape[0], 3):
plt.annotate(
df.index[line],
(df.Amanda.iloc[line], df.Ashley.iloc[line]+300 ) ,
va='bottom',
ha='center'
)
# x axis label
plt.xlabel('Amanda')
# y axis label
plt.ylabel('Ashley')
# show the graph
plt.show()
