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pythoncsvappendrows

Appending items at the end of each row in a CSV file


I'm trying to write a code that writes a CSV file that has, 1 header row, and 20 other rows, each one containing the following: 1 random name, 8 grades [randomly generated], and 1 final grade averaged from the other 8 random grades. I've gotten so far as to read the file and generate the average final grades and append it to an empty list so i can re-enter it to the file, but I'm having trouble writing/appending them back into the file.

I see that there is no x.writecolumns() and I'm having a lot of trouble trying to accomplish this step. Here is what i have so far. Thanks in advance for anyone that drops by to give advice on this.

import random
import csv

fname = ['Red', 'Jose', 'Mikasa', 'Sakura', 'Naruto', 'Momoka', 'Zero', 'Ryu', 'Ken', 'Geralt', 'Greg', 'Mika', 'Momo',
     'Xenovia', 'John', 'Gary', 'Lance', 'Eren', 'Duke', 'Claire']
lname = ['Akerman', 'Haruno', 'Johnson', 'Rivia', 'Valentine', 'Redfield', 'Kennedy', 'Juarez', 'Jameson', 'Williams',
     'Miller', 'Davis', 'Thompson', 'Garcia', 'Remington', 'Hayabusa', 'Strife', 'Armstrong', 'Kojima', 'Chambers']

avg_list = list() 
#^List where im appending all the average grades for all students

def ranint():
    value = random.randint(60, 100)
    return value
#^random value generator 

def ranname():
    first = random.choice(fname)
    last = random.choice(lname)
    fname.remove(first)
    lname.remove(last)
    return ("; ".join([first, last]))
#^picks a random first name and random last name

#CSV writer that has 1 header row and 20 other rows, each consisting of 1 name, 8 random grades, and 1 final grade averaged from the other 8
with open('grades2.csv', 'w', newline='') as fp:
a = csv.writer(fp, delimiter=',')
data = [['Name', 'If Else', 'Loops', 'Functions', 'File IO', 'Conditionals', 'Repetition', 'Python Functions',
         'Input Output', 'Grade'],
        [ranname(), ranint(), ranint(), ranint(), ranint(), ranint(), ranint(), ranint(), ranint()],
        [ranname(), ranint(), ranint(), ranint(), ranint(), ranint(), ranint(), ranint(), ranint()],
        [ranname(), ranint(), ranint(), ranint(), ranint(), ranint(), ranint(), ranint(), ranint()],
        [ranname(), ranint(), ranint(), ranint(), ranint(), ranint(), ranint(), ranint(), ranint()],
        [ranname(), ranint(), ranint(), ranint(), ranint(), ranint(), ranint(), ranint(), ranint()],
        [ranname(), ranint(), ranint(), ranint(), ranint(), ranint(), ranint(), ranint(), ranint()],
        [ranname(), ranint(), ranint(), ranint(), ranint(), ranint(), ranint(), ranint(), ranint()],
        [ranname(), ranint(), ranint(), ranint(), ranint(), ranint(), ranint(), ranint(), ranint()],
        [ranname(), ranint(), ranint(), ranint(), ranint(), ranint(), ranint(), ranint(), ranint()],
        [ranname(), ranint(), ranint(), ranint(), ranint(), ranint(), ranint(), ranint(), ranint()],
        [ranname(), ranint(), ranint(), ranint(), ranint(), ranint(), ranint(), ranint(), ranint()],
        [ranname(), ranint(), ranint(), ranint(), ranint(), ranint(), ranint(), ranint(), ranint()],
        [ranname(), ranint(), ranint(), ranint(), ranint(), ranint(), ranint(), ranint(), ranint()],
        [ranname(), ranint(), ranint(), ranint(), ranint(), ranint(), ranint(), ranint(), ranint()],
        [ranname(), ranint(), ranint(), ranint(), ranint(), ranint(), ranint(), ranint(), ranint()],
        [ranname(), ranint(), ranint(), ranint(), ranint(), ranint(), ranint(), ranint(), ranint()],
        [ranname(), ranint(), ranint(), ranint(), ranint(), ranint(), ranint(), ranint(), ranint()],
        [ranname(), ranint(), ranint(), ranint(), ranint(), ranint(), ranint(), ranint(), ranint()],
        [ranname(), ranint(), ranint(), ranint(), ranint(), ranint(), ranint(), ranint(), ranint()],
        [ranname(), ranint(), ranint(), ranint(), ranint(), ranint(), ranint(), ranint(), ranint()]]
a.writerows(data)
fp.close()

#Reads the file, sums all 8 grades and gets the average. Does this for all students and then appends the results to a empty list
with open('grades2.csv', 'r+', newline='') as fh:
z = csv.reader(fh)
next(z)   #skip the header
for row in z:
    integers = [int(i) for i in row[1:9]]
    avg_integers = sum(integers) / len(integers)
    avg_list.append(avg_integers)
    print(avg_integers) #This is just here to check with the final CSV file
fh.close()

Solution

  • I believe your only option here is to create a list of all row data with averaged grades, then clear the contents of the file and and re-write to the csv. See the code below which accomplishes this:

    import random
    import csv
    
    fname = ['Red', 'Jose', 'Mikasa', 'Sakura', 'Naruto', 'Momoka', 'Zero', 'Ryu', 'Ken', 'Geralt', 'Greg', 'Mika', 'Momo',
         'Xenovia', 'John', 'Gary', 'Lance', 'Eren', 'Duke', 'Claire']
    lname = ['Akerman', 'Haruno', 'Johnson', 'Rivia', 'Valentine', 'Redfield', 'Kennedy', 'Juarez', 'Jameson', 'Williams',
         'Miller', 'Davis', 'Thompson', 'Garcia', 'Remington', 'Hayabusa', 'Strife', 'Armstrong', 'Kojima', 'Chambers']
    
    avg_list = list() 
    #^List where im appending all the average grades for all students
    
    def ranint():
        value = random.randint(60, 100)
        return value
    #^random value generator 
    
    def ranname():
        first = random.choice(fname)
        last = random.choice(lname)
        fname.remove(first)
        lname.remove(last)
        return ("; ".join([first, last]))
    #^picks a random first name and random last name
    
    #CSV writer that has 1 header row and 20 other rows, each consisting of 1 name, 8 random grades, and 1 final grade averaged from the other 8
    with open('C:/react/learnnextjs-demo/pages/grades2.csv', 'w', newline='') as fp:
        a = csv.writer(fp, delimiter=',')
        data = [['Name', 'If Else', 'Loops', 'Functions', 'File IO', 'Conditionals', 'Repetition', 'Python Functions',
                 'Input Output', 'Grade'],
                [ranname(), ranint(), ranint(), ranint(), ranint(), ranint(), ranint(), ranint(), ranint()],
                [ranname(), ranint(), ranint(), ranint(), ranint(), ranint(), ranint(), ranint(), ranint()],
                [ranname(), ranint(), ranint(), ranint(), ranint(), ranint(), ranint(), ranint(), ranint()],
                [ranname(), ranint(), ranint(), ranint(), ranint(), ranint(), ranint(), ranint(), ranint()],
                [ranname(), ranint(), ranint(), ranint(), ranint(), ranint(), ranint(), ranint(), ranint()],
                [ranname(), ranint(), ranint(), ranint(), ranint(), ranint(), ranint(), ranint(), ranint()],
                [ranname(), ranint(), ranint(), ranint(), ranint(), ranint(), ranint(), ranint(), ranint()],
                [ranname(), ranint(), ranint(), ranint(), ranint(), ranint(), ranint(), ranint(), ranint()],
                [ranname(), ranint(), ranint(), ranint(), ranint(), ranint(), ranint(), ranint(), ranint()],
                [ranname(), ranint(), ranint(), ranint(), ranint(), ranint(), ranint(), ranint(), ranint()],
                [ranname(), ranint(), ranint(), ranint(), ranint(), ranint(), ranint(), ranint(), ranint()],
                [ranname(), ranint(), ranint(), ranint(), ranint(), ranint(), ranint(), ranint(), ranint()],
                [ranname(), ranint(), ranint(), ranint(), ranint(), ranint(), ranint(), ranint(), ranint()],
                [ranname(), ranint(), ranint(), ranint(), ranint(), ranint(), ranint(), ranint(), ranint()],
                [ranname(), ranint(), ranint(), ranint(), ranint(), ranint(), ranint(), ranint(), ranint()],
                [ranname(), ranint(), ranint(), ranint(), ranint(), ranint(), ranint(), ranint(), ranint()],
                [ranname(), ranint(), ranint(), ranint(), ranint(), ranint(), ranint(), ranint(), ranint()],
                [ranname(), ranint(), ranint(), ranint(), ranint(), ranint(), ranint(), ranint(), ranint()],
                [ranname(), ranint(), ranint(), ranint(), ranint(), ranint(), ranint(), ranint(), ranint()],
                [ranname(), ranint(), ranint(), ranint(), ranint(), ranint(), ranint(), ranint(), ranint()]]
        a.writerows(data)
        fp.close()
    
    #Reads the file, sums all 8 grades and gets the average. Does this for all students and then appends the results to a empty list
    with open('grades2.csv', 'r+', newline='') as fh:
    
        reader =  csv.reader(fh)
        next(reader)   #skip the header
        allRows = []
        for row in reader:
            integers = [int(i) for i in row[1:9]]
            avg_integers = sum(integers) / len(integers)
            row.append(avg_integers) #This is just here to check with the final CSV file
            allRows.append(row)
        fh.close()
        with open('grades2.csv', "w+", newline='') as fw:
            writer = csv.writer(fw)
            writer.writerows(allRows)
        fw.close()