#
# This program opens a file (the file name is supplied by the user) with numbers.
# Extracts them and stores them in a list.
# This program understands lines on numbers separated by space as well as number-per-line
# e.g.
# 1 21 32 12
# 9 0 -9 23 1
#  OR
# 1
# 21
# 32 ...

import string

def main():
    print "Hello!"
    print "This program opens a file with numbers, extracts all the numbers and stores them in a list." 
    print "The file name is supplied by the user."

    fname=raw_input("Please, input the name of the file with numbers:")
    inp=open(fname,'r')
 
    # loop in the numbers of lines in a file
    k=1
    numbers=[0]
    for line in inp:

        print "Next line from the file: %s" % line # displays the line taken from the input file

        #line_s=inp.readline() # reads a line from the input file

        # split the string into a list of numbers using " " as a dilimeter, assigns to numbers_in_line
        numbers_in_line=string.split(line," ")
        n=len(numbers_in_line) # finds the number of elements in the numbers_in_line list

        # runs through all the elements of numbers_in_line list and appends them to the list 'numbers',
        # the list of all numbers in the file
        # if a line ends with \n then this newline character is removed
        for i in range(n):
            m=len(numbers_in_line[i]) # finds the number of digits (including newline character)
                                      # in the the elemtns of the numbers_in_list list (not an elegant solution)
                                      # this is neened for the check for newline character
            # if we reached the last element in the list numbers_in_line, and the last "digit" is
            # newline character then we cut it off the number
            # this approach covers the case when the last line of numbers in the file doesn't end with \n
            if i==n-1 and numbers_in_line[i][m-1] == "": 
                #m=len(numbers_in_line[i])
                numbers.append(eval(numbers_in_line[i][:m-1]))
            else:
                #numbers[k]=eval(numbers_in_line[i])
                numbers.append(eval(numbers_in_line[i]))
            k=k+1;

    print "The numbers extracted from the file %s are:" % fname
    for i in range(k):
        print numbers[i]

    inp.close()

main()