CheckIO - Home Challenge 2 : Median

checkio.1.02.Median.py

# CheckIO - Home Challenge 2 : Median
# http://checkio.org

# A median is a numerical value separating the upper half of a sorted array of numbers from the lower half. 
# In a list where there are an odd number of entities, the median is the number found in the middle of the array. 
# If the array contains an even number of entities, then there is no single middle value, 
# instead the median becomes the average of the two numbers found in the middle. 
# For this mission, you are given a non-empty array of natural numbers (X). 
# With it, you must separate the upper half of the numbers from the lower half and find the median.

def checkio(data):
    
    data.sort() # Sorting list
    if (len(data)%2 == 0): # If list length is even 
        idx=int(len(data)/2)
        return (data[idx]+data[idx-1])/2
    else:                  # If list length is odd 
        return data[len(data)//2]

#These "asserts" using only for self-checking and not necessary for auto-testing
if __name__ == '__main__':
    assert checkio([1, 2, 3, 4, 5]) == 3, "Sorted list"
    assert checkio([3, 1, 2, 5, 3]) == 3, "Not sorted list"
    assert checkio([1, 300, 2, 200, 1]) == 2, "It's not an average"
    assert checkio([3, 6, 20, 99, 10, 15]) == 12.5, "Even length"
    print("Start the long test")
    assert checkio(list(range(1000000))) == 499999.5, "Long."
    print("The local tests are done.")