[curien]

Hello,
I am working on a code that takes the users input ( a string of digits) from the command line and prints out the median number. I am trying to accomplish this by:

from sys import argv

nums = argv[1:]


for index, value in enumerate(nums):
nums[index] = float(value)

print nums[1:] + nums[:1] / 2

I keep getting the error:
type error: unsupported operand type(s) for /: 'list' and 'int'

[Laharl]

Slicing always returns a list, even if that list only has one operator. As such, nums[1:] is a list, as is nums[:1].

The builtin sum(list, start=0) function will probably help you here.

[bvdet]

Originally Posted by curien

Hello,
I am working on a code that takes the users input ( a string of digits) from the command line and prints out the median number. I am trying to accomplish this by:

from sys import argv

nums = argv[1:]


for index, value in enumerate(nums):
nums[index] = float(value)

print nums[1:] + nums[:1] / 2

I keep getting the error:
type error: unsupported operand type(s) for /: 'list' and 'int'

First, let's consider the definition of the median number of a sequence of numbers. The median is the number where half of the numbers are larger and half are smaller. Therefore the list must be sorted. If the list contains an even number of items, the median is taken as the mean or average between the two middle numbers. The following function returns the median number from a sorted list of numbers:

Expand|Select|Wrap|Line Numbers

1. def median(s):
2.     i = len(s)
3.     if not i%2:
4.         return (s[(i/2)-1]+s[i/2])/2.0
5.     return s[i/2]

Example:

Expand|Select|Wrap|Line Numbers

1. >>> s1 = "100 45 89 23 105 220 45 66 8 75"
2. >>> s2 = "100 45 89 23 105 220 45 66 8 75 7"
3. >>> sList = [float(num) for num in s1.split()]
4. >>> sList.sort()
5. >>> median(sList)
6. 70.5
7. >>> sList
8. [8.0, 23.0, 45.0, 45.0, 66.0, 75.0, 89.0, 100.0, 105.0, 220.0]
9. >>> sList = [float(num) for num in s2.split()]
10. >>> sList.sort()
11. >>> median(sList)
12. 66.0
13. >>> sList
14. [7.0, 8.0, 23.0, 45.0, 45.0, 66.0, 75.0, 89.0, 100.0, 105.0, 220.0]
15. >>>