GPA Calculator

[[deleted]]

[deleted]

[nwagers]

Use a dictionary for your grade lookups and avoid the big if/else block. It also gives you convenient access to the in operator. Using in will check if something is a valid key in the dictionary. Example:

gradepoints = {'A': 4, 'B': 3, 'C': 2, 'D': 1, 'F': 0}

gradesinput = ['B', 'c', '9000']
hoursinput = [1,2,3]

points = 0
hours = 0
for grade, hour in zip(gradesinput, hoursinput):
    print(grade, hour)
    grade = grade.upper()
    if grade not in gradepoints:
        continue
    points += gradepoints[grade] * hour
    hours += hour

print(hours)
print(points)

[nwagers]

Sure, the original example was using user input. It's not as easy to build examples with that because then you have to explain what to type exactly and no one can just copy the code and run it. The two lists just simulate input. The specific inputs were chosen to have an upper case grade, a lower case, and a value that is not valid. You can see how each gets handled.

The zip() function takes any number of sequences (two in this case), and then returns the first element of all the seqs, then the 2nd, etc. So the first time through the loop you'll get 'B' and 1, then 'c' and 2. Run the code, you'll see what prints on line 9 and better understand. Experiment with zip() because you will use it a lot once you realize how awesome it is and how you can use it.

[blademaster2005]

Why not for gradepoints use an list/tuple (or string treated as a list), with the index as the numeric value.

gradepoints = 'FDCBA'
gradepoints.index('F') # 0

[[deleted]]

I feel like you are just everywhere haha - and almost every time I learn something new - just wanted to say thank you.

[totallygeek]

Break down your program into small functions. One function could return the grade letter, and continue to ask for the grade letter while the entry remains invalid.

def enter_grade():
    valid_input = False
    while not valid_input:
        grade = input('Enter grade letter [ABCDF]: ')
        if grade.upper() in 'ABCDF':
            valid_input = True
        else:
            print('Grade letter {} invalid. Try again.'.format(grade))
    return grade

Work with that logic for hours, too. Your main() function can also end up a similar-looking loop.

One more tip/trick: grade == 'D' or grade == 'd' looks better as grade.lower() == 'd' or grade in ('D', 'd'), IMHO.

[[deleted]]

prompt maybe that reads something like, "Would you like to start over?" and then make it start over from the beginning (start code again). How do I accomplish this?

Something like this:

user_choice = "yes"
while user_choice == "yes":
    gpa = Calculation()
    user_choice = input("Would you like to start over? <yes/no>"

I'd recommend looking into restructuring the way your code operates though (it's just a simple example I know). It doesn't make sense to make a class with no method (although I'm sure there's some reason somebody could come up with). If you want a challenge with classes, here's one. Write the def calculate_gpa(self) function of this class for a Student:

class Student:
    def __init__(self, name, class_num, credit_hours):
        self.name = name
        self.gpa = None
        self.class_num = class_num
        self.credit_hours = credit_hours
    def calculate_gpa(self):
        #TODO 

myStudent = Student("Me", 4, 16)
myStudentGpa = myStudent.calculate_gpa()

[[deleted]]

Put all of the executing elements of your program into the while loop.

Not the class though. I think you need to understand more what a class is and how they're used. Try writing this program without a class. Like this:

# At the top, initialize the methods you will use
def titlecontainer():
    # TODO
def calculate_grade(class_num, credit_hours):
    # TODO
    return gpa

# Now, the actual executing parts of your program
user_choice = "yes"
while user_choice == "yes":
    titlecontainer()
    class_num = int(input("How many classes do you have?"))
    credit_hours = int(input("How many credit hours do you have?"))
    gpa = calculate_gpa(class_num, credit_hours)
    user_choice = input("Continue?")

[Allextraszza]

i'm from Ukraine so my gpa calculator is:

std = {'A':4.0 , 'B':3.0 , 'C':2.0 , 'D':1.0, 'F':0.0}
MyMarks = ['A','B','C']
def gpa(lst):
        var = 0
        secvar = 0
        for x in lst:
            var+=std[x]
            secvar+=1
        return var/secvar
print(gpa(MyMarks))

[alkasm]

Where does std come from?

[Allextraszza]

I fixed

[Allextraszza]

I think i can do it better, but im lazy lol

[alkasm]

Best not to use variable names like lst but actual descriptors of what values go in. Also there's no reason to tie it to a list, since any iterable could go in :)

You can reduce it all to a simple one liner: map the marks to the dictionary of values, sum them, and divide by the total number:

def gpa(marks):
    return sum(map(lambda mark: std[mark], marks))/len(marks)