Python script to extract data from csv file

sharing the sample file screenshots, script I developed and other details below.

In the countries_source.csv file, I have a list of countries and I need a subset of its data created in mycountries.csv file until I hit the value “Asia” in the first column.

Using the below script, I was able to get the data till the 14th row – which is good. However, I need help with the below.

In the countries_source.csv file, I should get 17 to 21 rows as well based on the values in columns A and B – that is, every row that is a descendant of “South” (row 17) should be included in the mycountries.csv file as well. Other rows should be ignored.

import csv
import os

os.remove("C:/Users/Documents/Python Scripts/mycountries.csv")

with open("C:/Users/Documents/Python Scripts/countries_source.csv", "r") as source:
    csv_reader = csv.reader(source)
    lst=[]
    with open("C:/Users/Documents/Python Scripts/mycountries.csv", "w",newline='') as result:
        writer = csv.writer(result)
    #print(lst)
        for r in csv_reader:
            lst.append(r) 
        for ele in lst:
            if ele[0] != "Asia" :
                writer.writerow(ele)
            elif ele[0] == "Asia":
                break

Based on the data in countries_source.csv file and my requirement as discussed above, the expected result of mycountries.csv file screenshot is provided below.

Could you please help me with some ideas? – I’m new to coding, please excuse any obvious mistakes in the code. Thank you!

Answer

Create a boolean variable

check = True

And a List of south and its descendants

descendant = ["South"]

And replace your If and Elif with this

check = True
descendant = ["South"]

for ele in lst:
    if check:
        writer.writerow(ele)

    if ele[0] == "Asia":  
        check = False
    
    if ele[1] in descendants:
        writer.writerow(ele)
        descendant.append(ele[0])