checkio-medium

求中位数。先sort（）排序，对2取余数，判断余数是否是0。
注意的是在/运算中会自动保存成float，在调用比如data[len(data)/2]时候data里面的数必须是整形的，所以要int（）转换一下。

def checkio(data):
    x=len(data)%2
    data.sort()

    if x==0:
        y=len(data)/2
        data[0]=(data[int(y-1)]+data[int(y)])/2
    else:
        z=(len(data)-1)/2
        data[0]=data[int(z)]
    #replace this for solution
    return data[0]


#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.")