new to lists on python

Question

This is my current code:

while True:
        try:
            mylist = [0] * 7
            for x in range(7):
                    sales = float(input("Sales for day:"))
                    mylist[x] = sales
                    if  sales < 0:
                        print ("Sorry,invalid. Try again.")
        except:
            print ("Sorry, invalid. Try again.")
        else:
            break

print (mylist)

best = max(sales)
worst = min(sales)

print ("Your best day had", best, "in sales.")
print ("Your worst day had", worst, "in sales.")

When I run it I get this:

Sales for day:-5
Sorry,invalid. Try again.
Sales for day:-6
Sorry,invalid. Try again.
Sales for day:-7
Sorry,invalid. Try again.
Sales for day:-8
Sorry,invalid. Try again.
Sales for day:-9
Sorry,invalid. Try again.
Sales for day:-2
Sorry,invalid. Try again.
Sales for day:-5
Sorry,invalid. Try again.
[-5.0, -6.0, -7.0, -8.0, -9.0, -2.0, -5.0]
Traceback (most recent call last):
  File "C:/Users/Si Hong/Desktop/HuangSiHong_assign9_part.py", line 45, in <module>
    best = max(sales)
TypeError: 'float' object is not iterable

I am not quite sure how to code it so that, the lists do NOT take in negative values, because I only want values 0 or greater.

I am not sure how to solve the TypeError issue so that the min and max values will print as in my code

My last issue is, if I want to find the average value of the seven inputs that an user puts in, how should I go about this in pulling the values out of the lists

Thank you so much

Actually in Python 2.x you need `float(sum(my_list))/len(my_list)` -- otherwise, if all the values are integers, it rounds the average to an integer — Stuart, Dec 09 '12 at 23:18

PearsonArtPhoto · Accepted Answer · 2012-12-09T23:08:50.383

3

Your best bet is to put the data checking into a while loop. This will keep looping over this value until your conditions are met (>0)

Also, this could get confusing for the user to figure out what day they are entering the results for. Plus you need to be using the list for the max/min, not individual values. Put it all together, and make the following changes:

        for x in range(7):
            sales=-1
            while (sales<0):
                sales = float(input("Sales for day {0}".format(x)))
                mylist[x] = sales
                if  sales < 0:
                    print ("Sorry,invalid. Try again.")

And later make this change:

best = max(my_list)
worst = min(my_list)

edited Dec 09 '12 at 23:08

answered Dec 09 '12 at 23:03

PearsonArtPhoto

38,970
17
111
142

2

It might be a good idea to put in the day to the input-text as well (e.g. `'Sales for day {0}'.format(x+1)`) – poke Dec 09 '12 at 23:04
thanks for the help, but i was wondering what I can do in case the user enters something like "one hundred" instead of 100, @pearsonartphoto – user1762229 Dec 09 '12 at 23:26
http://stackoverflow.com/questions/354038/how-do-i-check-if-a-string-is-a-number-in-python – PearsonArtPhoto Dec 09 '12 at 23:38

score 3 · Answer 2 · answered Dec 09 '12 at 23:03

3

Did you mean to say:

best = max(my_list)
worst = min(my_list)

As to the validity check, the problem there is that if the input is invalid, you still move on to the next value of x.

answered Dec 09 '12 at 23:03

NPE

486,780
108
951
1,012

score -1 · Answer 3 · answered Dec 11 '12 at 01:04

maybe (untested):

mylist = []
while len(mylist) < 7:
    sales = float(input("Sales for day %s:" % str(len(mylist)+1)))
    if  sales >= 0:
        mylist.append(sales)
    else:
        print ("Sorry,invalid. Try again.")

print (mylist)

best = max(mylist)
worst = min(mylist)

print ("Your best day had", best, "in sales.")
print ("Your worst day had", worst, "in sales.")

new to lists on python

3 Answers3