def open_file():



    while(True):
        try:
            file_name = str(input('Enter a file name: '))
            file_obj = open(file_name,'r')
            L = []

            break

        except FileNotFoundError:
            print('Error. File not found.')

    for file_line in file_obj:
        L.append([float(x) for x in file_line.split(',')])


    # make sure to close file_obj.close()

    index = 0
    while(index < len(L)):
        if(len(L[0]) == len(L[index])):
            index+=1
        else:
            return('Data could not be loaded (the number of columns is not the same for all rows).')
            break


    print()
    col_num = len(L[0])
    row_index = 1
    alpha_index = 0
    alpha_str = 'ABCDEFGHIJKLMNOPQRSTUVWXYZ'
    blank = ' '

    print('|{:^5}'.format(blank), end = '')


    while(alpha_index < col_num):
        print('|{:^10}'.format(alpha_str[alpha_index]), end = '')
        alpha_index +=1

    print()

    for row in L:

        print('|{:^5}'.format(row_index), end ='')

        for elem in row:

            print('|{:^10.2f}'.format(elem),end = '')
        row_index+=1
        print()



    print()

    return(L)
def main():

    print('1 - Open and load from a file\n2 - Minimum\n3 - Maximum\n4 - Sum\n5 - Average\n6 - Sort (by column, ascending or decending)\n7 - Insert\n8 - Delete\n9 - Modify an element\n10 - Save\n11 - Save As (specify new file name)\n0 - Exit')

    while(True):

        task = (input('Your choice: '))
        if(task == '0' or task == '1' or task == '2' or task == '3' or task == '4' or task == '5' or task == '6'
        or task == '7'or task == '8'or task == '9' or task == '10' or task == '11'):

            break

    if(task == '0'):
        pass
    if(task == '1'):
        numlist = open_file()
        print(numlist)
        main()



main()