Question

The file cereal.scsv contains the nutritional information for over 70 cereals. However it's in a format that is rarely used (semi-colon separated values). The reason it's in this format is that a few cereals have commas in their name (e.g. Fruit & Fibre Dates, Walnuts, and Oats). There is a separate lesson on converting this data to a proper csv format.

Also note that the first line identifies the column names; the second line identifies the data types for each column.

Part 1 reading and finding

Create

Create a function named find_total_for that has two parameters (in this order):

• filename_in which is the path the file to read
• column_name which is the name of the column of data we are interested in

Read the data, parse the data

find_total_for will read in the file and sum up the values identified by column_name.

Notes and Hints:

• only columns that have numeric values will be requested
• open and read the .scsv file (i.e. filename_in)
• parse out each line into its separate components

Return

The function returns the sum of values for column column_name

(In Python)

Answer 1

The following function uses the simple concepts of file handling and split function to get the required information from the file.


def find_total_for(filename_in,column_name):
    # Opening file as f
    f = open(filename_in)
    
    # Function to store all lines in a list
    rows = f.readlines()
    
    # To remove "\n" from end of each string
    for i in range(len(rows)-1):
        rows[i] = rows[i][:len(rows[i])-1]

    # Counter of column
    c = 0
    
    # Different column names given in first line
    columns = rows[0].split(";")
    
    # Getting the index of the required column 
    for column in columns:
        if(column==column_name):
            req_column = c
            break
        c+=1
    
    summ = 0
    
    #Adding up the values from each row
    for i in range(1,len(rows)):
        col = rows[i].split(";")
        summ += int(col[req_column])
    
    return summ