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Pandas Datetime: Create a heatmap for comparison of the top 10 years in which the UFO was sighted vs each Month

Pandas Datetime: Exercise-24 with Solution

Write a Pandas program to create a heatmap (rectangular data as a color-encoded matrix) for comparison of the top 10 years in which the UFO was sighted vs each Month.

Sample Solution:

Python Code:

import pandas as pd
import matplotlib.pyplot as plt
import seaborn as sns
#Source: https://bit.ly/1l9yjm9
df = pd.read_csv(r'ufo.csv')
df['Date_time'] = df['Date_time'].astype('datetime64[ns]')
most_sightings_years = df['Date_time'].dt.year.value_counts().head(10)
def is_top_years(year):
   if year in most_sightings_years.index:
       return year
month_vs_year = df.pivot_table(columns=df['Date_time'].dt.month,index=df['Date_time'].dt.year.apply(is_top_years),aggfunc='count',values='city')
month_vs_year.columns = month_vs_year.columns.astype(int)
print("\nHeatmap for comparison of the top 10 years in which the UFO was sighted vs each month:")
plt.figure(figsize=(10,8))
ax = sns.heatmap(month_vs_year, vmin=0, vmax=4)
ax.set_xlabel('Month').set_size(20)
ax.set_ylabel('Year').set_size(20)

Sample Output:

Heatmap for comparison of the top 10 years in which the UFO was sighted vs each month:
Create a heatmap for comparison of the top 10 years in which the UFO was sighted vs each Month

Python Code Editor:


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Previous: Write a Pandas program to create a comparison of the top 10 years in which the UFO was sighted vs each Month.
Next: Write a Pandas program to create a Timewheel of Hour Vs Year comparison of the top 10 years in which the UFO was sighted.

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Python: Tips of the Day

Find current directory and file's directory:

To get the full path to the directory a Python file is contained in, write this in that file:

import os 
dir_path = os.path.dirname(os.path.realpath(__file__))

(Note that the incantation above won't work if you've already used os.chdir() to change your current working directory, since the value of the __file__ constant is relative to the current working directory and is not changed by an os.chdir() call.)

To get the current working directory use

import os
cwd = os.getcwd()

Documentation references for the modules, constants and functions used above:

  • The os and os.path modules.
  • The __file__ constant
  • os.path.realpath(path) (returns "the canonical path of the specified filename, eliminating any symbolic links encountered in the path")
  • os.path.dirname(path) (returns "the directory name of pathname path")
  • os.getcwd() (returns "a string representing the current working directory")
  • os.chdir(path) ("change the current working directory to path")

Ref: https://bit.ly/3fy0R6m