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Python Set Operations Explained: From Theory to Real-Time Applications

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A  set  in Python is an unordered collection of unique elements. It is useful when storing distinct values and performing operations like union, intersection, or difference. Real-Time Example: Removing Duplicate Customer Emails in a Marketing Campaign Imagine you are working on an email marketing campaign for your company. You have a list of customer emails, but some are duplicated. Using a set , you can remove duplicates efficiently before sending emails. Code Example: # List of customer emails (some duplicates) customer_emails = [ "alice@example.com" , "bob@example.com" , "charlie@example.com" , "alice@example.com" , "david@example.com" , "bob@example.com" ] # Convert list to a set to remove duplicates unique_emails = set (customer_emails) # Convert back to a list (if needed) unique_email_list = list (unique_emails) # Print the unique emails print ( "Unique customer emails:" , unique_email_list) Ou...

How to Read CSV file Data in Python

Here is a way to read CSV files in Python pandas. The packages you need to import are numpy and pandas. On the flip side, for Text files, you don't need to import these special libraries since python by default support it.



pandas read_csv


Python pandas read_csv


>>> import numpy as np
>>> import pandas as pd


To see how pandas handle this kind of data, we'll create a small CSV file in the working directory as ch05_01.csv.

white, red, blue, green, animal
1,5,2,3,cat 
2,7,8,5,dog 
3,3,6,7,horse 
2,2,8,3,duck 
4,4,2,1,mouse


Since this file is comma-delimited, you can use the read_csv() function to read its content and convert it to a dataframe object.
>>> csvframe = pd.read_csv('ch05_01.csv')
>>> csvframe
   white  red  blue  green animal
0      1    5     2      3    cat
1      2    7     8      5    dog
2      3    3     6      7  horse
3      2    2     8      3   duck
4      4    4     2      1  mouse


Python reading text files


Since python supports text files, you don't need to import NumPy and Pandas. The syntax is a little different. 

Using the Open method, here file is opened with read mode. In the place file name, it has given; the full path of the file. The Print method displays contents. Here read method is used to read the file.

# Open our file in read mode 
f = open("data/flatland01.txt", mode="r") 
# Read and display the text file 
print(f.read())
# Close our file resource 
f.close()

Finally, working with CSV and Text files knowing is helpful for interviews.


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