column_data = [row[1] for row in reader] column_data = list(map(int, column_data[1:]))

These two lines of code are reading data from a CSV file using the csv.reader function and then converting the second column of the data into a list of integers.

The first line uses a list comprehension to iterate over each row in the CSV file and extract the second column (index 1) into a new list called column_data.

The second line uses the built-in map function to apply the int function to each element in column_data (excluding the first element, which is a header) and return a new list of integers. This new list is then assigned to column_data.

Overall, these lines of code are useful for extracting and converting specific columns of data from a CSV file for further analysis or manipulation.