Explanation of code.txt

#importing necessary packages
    import kaggle
    import pandas as pd

#used to download zipfile - dataset which are available in kaggle
    !kaggle datasets download ankitbansal06/retail-orders -f orders.csv

#extract file from zip file
    import zipfile
    zip = zipfile.ZipFile('orders.csv.zip')
    zip.extractall()
    zip.close()

#read a csv and handle null values present in the dataset
    df = pd.read_csv('orders.csv', na_values=['Not Available', 'unknown'])
#checking how much values available inside the ship mode column
    df['Ship Mode'].unique()

#rename column names - make all into lower case & replace with underscore
#high time complexity, because takes time to change all columns
    df.rename(columns = {'Order Id' : 'order_id'})

#instead change into str and use lower()
        df.columns = df.columns.str.lower()

#replace all spaces with underscore
    df.columns = df.columns.str.replace(' ', '_')
    df.head(5)