Python Decimal Places easy

Question

I feel a bit blonde right now, but for some reason I can't figure out how to solve this.

Need to correct these two issues.

using // integer division messes up the average.

Also, I need to use the format function to get 2 decimal places

def viewscores(scores):

sum_scores = sum(scores)
average = float(sum_scores // len(scores))
### here is where I am having the results displayed

print ("The scores are these: " + str(scores))
print ("The Average score now is: " + str(average))

def main():

scores = []

scores_file = open('scores.txt', 'r')
line_list = list(scores_file.readlines())

scores_file.close()
i = 0
while i < len(line_list):
    scores.append(int(line_list[i].strip()))
    i += 1
viewscores(scores)

main()

If `sum_score` is an integer, then make it a float before you divide it by an integer. Mess around with dividing with integers, and you will see why. — , Jun 24 '15 at 03:06
Don't use _floored_ division. [Format string syntax](https://docs.python.org/3/library/string.html#format-string-syntax). — wwii, Jun 24 '15 at 03:13

score 2 · Answer 1 · answered Jun 24 '15 at 03:26

This is one of those things where Python2 and Python3 behave differently.

using // integer division messes up the average.

Python 3:

average = sum_scores / len(scores)

Python 2:

average = float(sum_scores) / len(scores)

In either case, you don't want to use //.

Also, I need to use the format function to get 2 decimal places

Python 3:

print ('The average score now is {:.2f}'.format(average))

Python 2:

print ('The average score now is %.2f' % average)

Even within each dialect there's multiple solutions.

Don't forget that you can make Python 2's `/` operator behave like Python 3's with `from __future__ import division`. — dan04, Jun 24 '15 at 03:58

score 0 · Answer 2 · answered Jun 24 '15 at 03:12

The most simple option would be to use format(scores, '.2f')

sum_scores = float(sum(scores))
average = (sum_scores / float(len(scores)))


print ("The scores are these: %s" %format(scores, '.2f'))
print ("The Average score now is: %s"  %format(average, '.2f')

score 0 · Answer 3 · edited May 23 '17 at 11:58

i am new to Python as well.

For "//", i gave a trial on ipython, to me they do not make much difference whether you use // or /

using "/" http://screencloud.net/v/hcDo
using "//" http://screencloud.net/v/bwAq
the solution to your request is http://screencloud.net/v/rwQp

For two decisoinal place problem, i learnt something from the following

Limiting floats to two decimal points
and it works to your case - http://screencloud.net/v/1gPB

For function, you may wish to consult Google

i am not good at creating function, but function always should have "return", because everything in python is object

Python Decimal Places *easy*

3 Answers3

Python Decimal Places easy