File15. Дан файл вещественных чисел. Найти сумму его элементов с четными номерами.

Решение на Python 3:

def EmptyFile(fname):
    open(fname, 'w').close()
    
def Write2File(fname,lst):
    try:
        f = open(fname, "a")
        try:
            for line in lst:
                f.write(line)
        finally:
            f.close()
    except IOError:
        print('Write error: ',fname)

f_source = "file15_source.txt"
f_even = "file15_even.txt"
f_odd = "file15_odd.txt"
EmptyFile(f_even)
EmptyFile(f_odd)

try:
    with open(f_source,'r') as f:
        lines = f.readlines()
        #print(lines)
        l_even = lines[::2]
        l_odd = lines[1::2]
        print(l_even)
        print(l_odd)
        Write2File(f_even,l_even)
        Write2File(f_odd,l_odd)
        float_even = list(map(float, l_even)) 
        float_odd = list(map(float, l_odd)) 
        print("sum of evens:",sum(float_even))
        print("sum of odds:",sum(float_odd))
except IOError:
    print('Open error: ',f_source)