File28. Дан файл вещественных чисел. Заменить в файле каждый элемент, кроме начального и конечного, на его среднее арифметическое с предыдущим и последующим элементом.

Решение на Python 3:

# -*- coding: utf-8 -*-
import random

def GenerateReals(fname):
#generate random real numbers and save them to file
    N = random.randint(2,15)
    #N = 9
    print("N = ",N)
    L = []
    x = round(random.uniform(0, 10),1)
    L.append(x)
    for i in range(1,N):
        lst_rnd = [round(random.uniform(0, 10),1) for _ in range(0,10)]
        try:
            lst_rnd.remove(x)
        except:
            pass
        x = random.choice(lst_rnd)
        L.append(x)
    print(L)
    try:
        f = open(fname, "w")
        try:
            for x in L:
                line = str(x)+"\n"
                f.write(line)
        finally:
            f.close()
    except IOError:
        print('Write error: ',fname)

f_input = "file28_in.txt"
f_output = "file28_out.txt"
GenerateReals(f_input)
print("Read from:",f_input)
print("Write to:",f_output)

try:
    with open(f_input, 'r') as f_in, open(f_output, 'w') as f_out:
        line = f_in.readline()
        x1 = float(line.strip())
        f_out.write(line)
        line = f_in.readline()
        x2 = float(line.strip())
        for line in f_in:
            x = float(line.strip())
            x_avg = (x1 + x2 + x) / 3
            s_avg = str(x_avg)+"\n"
            f_out.write(s_avg)
            x1 = x2
            x2 = x
        f_out.write(line)

except IOError:
    print('Open error: ',file1)