Convert a range score into a letter grade in Python

Question

I am trying to write a program that will convert a score between 0.0 and 1.0 into a letter grade. If the score is out of range, print an error message. If the score is between 0.0 and 1.0, print a letter grade using the following:

Score   Grade
>= 0.9  A
>= 0.8  B
>= 0.7  C
>= 0.6  D
<0.6    F

Requirements:

Use the “input” command to take in user input for score
check input to ensure that the score is in the rage of (0.0 to 1.0), if outside the rage - should output "Bad score"
The supplied input is of type string by default, so it must be converted to the float type
Should also catch a non-numeric input and print a “Bad score” error message.

This is the code I have as of now:

import sys
scores = input ("Enter your score: ")

try:
    floatScores = float(scores)
except:
    print ("Bad Score")

if floatScores >= 0.0 and floatScores < 0.4:
    print ("You have a: F")
elif floatScores >= 0.6 and floatScores < 0.7:
    print ("You have a: D")
elif floatScores >= 0.7 and floatScores < 0.8:
    print ("You have a: C")
elif floatScores >= 0.8 and floatScores < 0.9:
    print ("You have a: B")
elif (floatScores >= 0.9 and floatScores <= 1.0:
    print ("You have an: A")

else:
     print ("Bad Score")

sys.exit()

Please advice. Thanks

http://stackoverflow.com/questions/36218708/how-to-do-about-array-list-in-order-to-make-int-list-float-in-python/36218791#36218791 — Padraic Cunningham, Mar 27 '16 at 20:23
This isn't a "Do my homework for me" service... You've shown no effort solving this. Try writing the code yourself, include it in the question and explain what's not working, and why — Basic, Mar 27 '16 at 20:29

score 0 · Accepted Answer · edited May 23 '17 at 12:31

0

I'm not going to do your homework for you, however, I will give you a few hints...

Your first requirement states that you need to use the input command to take user input for the score. You know how to set a variable to an input, so start with that.
Next, you need to check if the score is within 0.0-1.0. You can use an if statement checking if your input is greater than or equal to 0, and less than or equal to 1.
For your third requirement, I recommend you read this post.
For your fourth requirement, I recommend you use a try-except or assert functionality of Python.

Edit

Now that you've posted some code I can help you.

In your elif (floatScores >= 0.9 and floatScores <= 1.0: you don't need the ( so get rid of that.

Then your code will work fine! :)

Note

Here is a slightly different way to do it if you don't want that long chain of if-elifs.

def range_score():
    score_range = {'A': 0.9, 'B': 0.8, 'C': 0.7, 'D': 0.6, 'F': 0.0}
    try:
        score = float(input('Score? '))
    except ValueError:
        return 'Bad Score'

    assert 0.0 <= score <= 1.0, 'Bad Score'

    for k, v in score_range.items():
        if score >= v:
            return k

edited May 23 '17 at 12:31

Community

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answered Mar 27 '16 at 20:40

Jason

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Thank you! That was simple.. I am not sure how i missed the "(" Thanks for the correction. – IronBat Mar 27 '16 at 21:01
@IronBat If I helped you please mark this as the "best answer" using the gray checkmark underneath the voting on the answer! :) – Jason Mar 27 '16 at 21:01
I am getting an error when I enter a non-numeric value.. Not sure what it means. Can you tell me what could be causing that? Enter your score: six Bad Score Traceback (most recent call last): File "C:/Users/score.py", line 22, in if floatScores >= 0.0 and floatScores < 0.6: NameError: name 'floatScores' is not defined – IronBat Mar 27 '16 at 22:27
It's because after you catch the error the program continues without `floatScores` being defined. I recommend you put a break at the end of your `except: print('Bad score')`. So `except: print('Bad Score') break` – Jason Mar 27 '16 at 22:30
This code is not robust. `dict` is not an ordered collection, so you have no guarantee that the (key, value) pairs will be returned by `score_range.items()` in the same order as they have in the `dict` literal. Try this: `print({'0':0, '1':1, '2':2, '3':3, '4':4})`; the results probably won't be in numerical order, and may vary from run to run depending on Python version, or if the `-R` option is given on the command line in older Python versions. – PM 2Ring Apr 19 '16 at 11:19

Convert a range score into a letter grade in Python

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