Need help writing and reading files and storing data into lists

Question

I need help with a weighted grade calculator, i have the bits that i need to calculate the data and the weighted averages. My problem is importing the data and storing it. I think i need to use lists but im just not sure how to separate each entry, I know I can use .split() and i will probably do that. But my real problem is figuring out how to store these values and then write to an output file.

So this is what the .txt file will look like for the input that i am importing to my program with a "open("scores.txt","r")" command

Babbage, Charles
10.0   9.5    8.0  10.0
 9.5  10.0    9.0
85.0  92.0   81.0
Turing, Alan
10.0   8.0    6.0
10.0  10.0    9.0   9.5
90.0  92.0   88.5
Hopper, Grace
10.0  10.0    8.0
10.0  10.0    9.0   9.5
90.0  92.0   88.0
Van Rossum, Guido
 7.5   8.5
 7.5   8.5    6.0   9.0
68.0  81.0   70.0
Backus, John
 9.5   9.5   10.0   8.0   9.5  10.0
 7.5   8.5    6.0   9.0  10.0
99.0  93.0  100.0
Crawley, Bryan
 6.0
 7.5
70.0  60.0   55.5

I tried using s.isdigit and s.isalpha and that didnt really work. 1st line is quizzes, 2nd line is projects, and third is exams. Number of quizzes and exams are arbitrary, the exams will always have three.

Here's what the output needs to look like:

Babbage, Charles      89.4   B
Turing, Alan          91.3   A
Hopper, Grace         92.7   A
Van Rossum, Guido     75.5   C
Backus, John          94.4   A
Crawley, Bryan        63.9   D

Here is what my code looks like now:

quiz_scores = []

while True:
    score = float(input("Quiz #{} ----- ".format(len(quiz_scores)+1)))
    if score == -1:
        break
    quiz_scores.append(score)
quiz_total = sum(quiz_scores) - min(quiz_scores)
if len(quiz_scores)>1:
    quiz_avg =  (quiz_total/((len(quiz_scores))-1)*10)
else:
    quiz_avg = (quiz_total/(len(quiz_scores)*10)

print()

project_scores = []

while True:
    score2 = float(input("Project #{} -- ".format(len(project_scores)+1)))
    if score2 == -1:
        break
    project_scores.append(score2)

project_total = sum(project_scores)
project_avg = (project_total/(len(project_scores))*10)

print()

exam1 = float(input("Exam #1 ----- "))
exam2 = float(input("Exam #2 ----- "))


print()

final = float(input("Final Exam -- "))

average = ((quiz_avg*.15)+(project_avg*.20)+(exam1*.20)+(exam2*.20)+(final*.25))

print("Average ---- %.2f" % average)



if 90 <= average <= 100:
    print("Grade ------- A")
if 80 <= average < 90:
    print("Grade ------- B")
if 70 <= average < 80:
    print("Grade ------- C")
if 60 <= average < 70:
    print("Grade ------- D")
if 0 <= average < 60:
    print("Grade ------- F")

Definitely looking to learn here, not just copy and paste what you comment; so please bear with me if i have some questions for you.

Thank you guys, this community has been very helpful.

Answer 1

you may want to use .csv instead. By importing csv or pandas, you can save/load data to/from csv files.

see official documents for more details.

Answer 2

Edit: I have removed the usage of NumPy and Pandas. If you want more detailed or specific answers to your question, you should update your original question or put in the comments.

If you can't choose how your data input looks like before making it, like @martineau suggested, you could do something like this:

# Ordered dictionary will let us add keys to a dictionary {}, but if we
# access the keys, it will retain the order we added them, which is not
# the default behaviour of a normal dict.
from collections import OrderedDict

# Load the file and sequentially add lines for users. You can simplify
# if they always have 3 lines each
with open('scores.txt') as f:

    out_dict = OrderedDict()
    # Load in each line from the file
    for line in f.readlines():

        # remove commas, replace(), strip newline characters '\n', strip();
        # split the line on spaces '81 81 30' -> ['81', '81', '30']
        line_split = [i for i in line.strip().replace(',', '').split(' ') if i != '']

        # From your current format, we know that some lines start with a character when there is a name, or a digit if it is a number
        # float('4') will give 4
        # float('s') will raise a ValueError exception
        #

        try:
            # If we do not raise an exception, we know it is an integer/float
            vals = [float(i) for i in line_split]
            # We can keep adding the values to the last entry in our dictionary, i.e., to the last name we created
            # As we used OrderedDict, we do not have to worry that we will retrieve a random key.
            out_dict[[i for i in out_dict.keys()][-1]].extend(vals)
        except ValueError:
            # So, if we raise an exception, we know it is 'Charles Babbage'
            # A new name is a new key, so put a new key in out_dict, and make the value a list we can keep adding to
            out_dict[line.strip()] = []

Then you can play around with this dictionary however you like. You can also make get_score and get_grade to work as you want, for now I just took the average as I didn't fully understand your intention....

# Some functions to define how the score and grading works
def get_score(scores):
    return sum(scores)/(1.0*len(scores))

def get_grade(score):
    if 90 <= score <= 100:
        return 'A'
    if 80 <= score < 90:
        return 'B'
    if 70 <= score < 80:
        return 'C'
    if 60 <= score < 70:
        return 'D'
    if 0 <= score < 60:
        return 'E'

for key, item in out_dict.items():
    print(key, get_score(item), get_grade(get_score(item)))

The output will look like:

Babbage, Charles 32.4 E
Turing, Alan 33.3 E
Hopper, Grace 33.65 E
Van Rossum, Guido 29.5555555556 E
Backus, John 27.8214285714 E
Crawley, Bryan 39.8 E

Answer 3

Hopefully you can grok what has been done here.. if you have any questions let me know.

gradebook={}
input_name = input("Enter input file:")
output_name = input("Enter input file:")

with open(input_name,"r") as file:
    for line in file:
        if line[0].isalpha():
            gradebook[line.strip()] = {'quizzes':next(file).strip().split(' '), 
                                        'projects':next(file).strip().split(' '), 
                                        'tests':next(file).strip().split(' ')
                                        }
for student, values in gradebook.items():
    quizzes = []
    projects = []
    tests = []
    for category, grades in values.items():
        for grade in grades:
            if grade != '':
                exec("%s.append(float(grade))"% category)
                # ^^^ THIS IS THE SAME AS THE FOLLOWING 
                #if category == 'quizzes':
                #   quizzes.append(float(grade))
                #if category == 'projects':
                #   projects.append(float(grade))
                #if category == 'tests':
                #   tests.append(float(grade))

    quiz_total = sum(quizzes) - min(quizzes)

    if len(quizzes)>1:
        quiz_avg =  (quiz_total/((len(quizzes))-1)*10) 
    else:
        quiz_avg = (quiz_total*10) #no reason to divide by len(quizzes) if it is 1

    project_total = sum(projects)
    project_avg = (project_total/(len(projects))*10)

    exam1 = tests[0]
    exam2 = tests[1]
    final = tests[2]

    average = ((quiz_avg*.15)+(project_avg*.20)+(exam1*.20)+(exam2*.20)+(final*.25))

    if 90 <= average <= 100:
        final_grade = "A"
    if 80 <= average < 90:
        final_grade = "B"
    if 70 <= average < 80:
        final_grade = "C"
    if 60 <= average < 70:
        final_grade = "D"
    if 0 <= average < 60:
        final_grade = "F"

    with open(output_name,"a") as file:
        file.write("{0:20} {1:0.1f} {2:>4}\n".format(student, average, final_grade))

This outputs the following:

Babbage, Charles     89.4    B
Turing, Alan         91.3    A
Hopper, Grace        92.7    A
Van Rossum, Guido    75.5    C
Backus, John         94.3    A
Crawley, Bryan       54.9    F

Not sure why Bryan Crawley's grade is lower than you expected?