Easy python program

Question

The user is prompted for a file, which in this case is 'histogram.txt'. The program takes each score in the text file and makes a histogram out of all the grades in the file, organizing them so that the user can see how many of each range there are. I wrote out a very simple code:

filename = raw_input('Enter filename of grades: ')

histogram10 = 0
histogram9 = 0
histogram8 = 0
histogram7 = 0
histogram6 = 0
histogram5 = 0
histogram4 = 0
histogram3 = 0
histogram2 = 0
histogram1 = 0
histogram0 = 0

for score in open(filename):
    if score >= 100:
        histogram10 = histogram10 + 1
    elif score >= 90: 
        histogram9 = histogram9 + 1
    elif score >= 80:
        histogram8 = histogram8 + 1
    elif score >= 70:
        histogram7 = histogram7 + 1
    elif score >= 60:
        histogram6 = histogram6 + 1
    elif score >= 50:
        histogram5 = histogram5 + 1
    elif score >= 40:
        histogram4 = histogram4 + 1
    elif score >= 30:
        histogram3 = histogram3 + 1
    elif score >= 20:
        histogram2 = histogram2 + 1
    elif score >= 10:
        histogram1 = histogram1 + 1
    elif score >= 0:
        histogram0 = histogram0 + 1

print    
print 'Grade Distribution'
print '------------------'
print '100     :',('*' * histogram10)
print '90 - 99 :',('*' * histogram9)
print '80 - 89 :',('*' * histogram8)
print '70 - 79 :',('*' * histogram7)
print '60 - 69 :',('*' * histogram6)
print '50 - 59 :',('*' * histogram5)
print '40 - 49 :',('*' * histogram4)
print '30 - 39 :',('*' * histogram3)
print '20 - 29 :',('*' * histogram2)
print '10 - 19 :',('*' * histogram1)
print '00 - 09 :',('*' * histogram0)

however whenever i run the program, all twenty grades get recorded onto the >= 100 like this:

100    : ********************
90-99  : 
80-89  :

etc. ... How do I make it so that the program puts the stars in the correct places?

Always step 1: make sure the data that is getting into the program is correct. — Jonathon Reinhart, Mar 29 '12 at 05:14
A little tip: Instead of having 11 different variables for the histogram, you could use a list and calculate the index, e.g. `histogram[min(100, score) / 10] += 1`. The `min` is to put all scores above 100 in the same slot. For more general data, like counting the number of words in a text, you could use a dictionary. — Some programmer dude, Mar 29 '12 at 05:22
[Any number is always less than any string in Python 2.](http://stackoverflow.com/questions/7969552/why-does-4-3-return-true-in-python-2) — agf, Mar 29 '12 at 06:38
One liner just for fun `any(__import__('sys').stdout.write('<= {} \t {}\n'.format(i * 10 + 10, '*' * num)) for i, num in ((k, len(list(g))) for k, g in __import__('itertools').groupby( sorted(int(score.strip()) for score in open(raw_input('Enter filename of grades: '))), key = lambda score: (score - 1) / 10)))`. — agf, Mar 29 '12 at 06:50

score 4 · Answer 1 · answered Mar 29 '12 at 05:15

4

Data read from a file is a string. Convert it to an integer first by passing it to int().

>>> int('25')
25

answered Mar 29 '12 at 05:15

Ignacio Vazquez-Abrams

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taskinoor · Accepted Answer · 2012-03-29T05:34:16.070

2

You need to convert score to int before comparing.

score = int(score)  # convert to int
if score >= 100:
    histogram10 = histogram10 + 1
# other cases

If you have blank lines in input file then you have to add necessary check before converting to int. Also instead of ten different variables you can easily use a list.

edited Mar 29 '12 at 05:34

answered Mar 29 '12 at 05:18

taskinoor

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thank you for this i also appreciate the advice. im still very new at compsci :P if you don't mind can you explain how to use a list with this? – Kim Y Mar 29 '12 at 05:22
1

Please go through the list tutorial http://docs.python.org/tutorial/introduction.html#lists. For `histogram0` you can use `l[0]`, for `histogram1` you can use `l[1]` and so on. – taskinoor Mar 29 '12 at 05:27

Easy python program

2 Answers2