Writing simultaneously, into several files, the el

Question

I have several lists:

VOLUMES =  ['119.823364', '121.143469']
P0 =  ['4.97568007', '4.98494429']
P2 =  ['16.76591397', '16.88768068']
Xs =  ['0.000000000000E+00', '3.333333333333E-01', '-4.090760942850E-01', '0.000000000000E+00', '3.333333333333E-01', '-4.093755657782E-01']
Ys =  ['0.000000000000E+00', '-3.333333333333E-01', '-3.333333333333E-01', '0.000000000000E+00', '-3.333333333333E-01', '-3.333333333333E-01']
Zs =  ['0.000000000000E+00', '-8.333333333333E-02', '-8.333333333333E-02', '0.000000000000E+00', '-8.333333333333E-02', '-8.333333333333E-02']
ATOMIC_NUMBERS =  ['20', '6', '8', '20', '6', '8']

And I would like to generate 2 files, named with the item of the VOLUMES list: 119.823364.dat and 121.143469.dat, such as each one contain the following:

119.823364.dat file:

some stuff
other stuff
4.97568007   16.76591397
3
20 0.000000000000E+00    0.000000000000E+00   0.000000000000E+00
6  3.333333333333E-01   -3.333333333333E-01  -8.333333333333E-02
8 -4.090760942850E-01   -3.333333333333E-01  -8.333333333333E-02
other stuff
some other stuff

121.143469.dat file:

some stuff
other stuff
4.98494429  16.88768068
3
20 0.000000000000E+00    0.000000000000E+00   0.000000000000E+00
6  3.333333333333E-01   -3.333333333333E-01  -8.333333333333E-02
8 -4.093755657782E-01   -3.333333333333E-01  -8.333333333333E-02
other stuff
some other stuff

There is the following issue:

len(VOLUMES) = len(P0) = len(P2) = 2

But:

len(Xs) = len(Ys) = len(Zs) = 6

I have managed to achieve the first part:

# Remove *.dat files, to clean first: 
for f in glob.glob("*.dat"):
    os.remove(f)

# Create the files:
filenames = []
for V in VOLUMES:
    filename = "{}.dat".format(V)
    print 'filename = ', filename
    filenames.append(filename)
print filenames

# Write to files:
for i in xrange(len(P0)):
       with open(filenames[i],'w') as f:
        f.write("""some stuff
other stuff\n""")
        f.write("{} {}\n".format(P0[i], P2[i]))
        f.write("{}\n".format(N_atom_irreducible_unit))

Which creates the following:

119.823364.dat file:

some stuff
other stuff
4.97568007 16.76591397
3

121.143469.dat file:

some stuff
other stuff
4.98494429 16.88768068
3

I cannot manage to write the information from Xs, Ys, Zs and ATOMIC_NUMBERS because these 4 lists have different length than both P0 and P2.

I managed to re-write Xs, Ys, Zs and ATOMIC_NUMBERS into one single list of list of lists:

for index_vol in range(len(VOLUMES)):
  for index in range(len(ATOMIC_NUMBERS)):
    atoms_per_frame = [ATOMIC_NUMBERS[index], Xs[index], Ys[index], Zs[index]]
    atoms_all_frames[index_vol].append(atoms_per_frame)

print atoms_all_frames  

which prints the following:

[[['20', '0.000000000000E+00', '0.000000000000E+00', '0.000000000000E+00'], ['6', '3.333333333333E-01', '-3.333333333333E-01', '-8.333333333333E-02'], ['8', '-4.090760942850E-01', '-3.333333333333E-01', '-8.333333333333E-02'], ['20', '0.000000000000E+00', '0.000000000000E+00', '0.000000000000E+00'], ['6', '3.333333333333E-01', '-3.333333333333E-01', '-8.333333333333E-02'], ['8', '-4.093755657782E-01', '-3.333333333333E-01', '-8.333333333333E-02']], [['20', '0.000000000000E+00', '0.000000000000E+00', '0.000000000000E+00'], ['6', '3.333333333333E-01', '-3.333333333333E-01', '-8.333333333333E-02'], ['8', '-4.090760942850E-01', '-3.333333333333E-01', '-8.333333333333E-02'], ['20', '0.000000000000E+00', '0.000000000000E+00', '0.000000000000E+00'], ['6', '3.333333333333E-01', '-3.333333333333E-01', '-8.333333333333E-02'], ['8', '-4.093755657782E-01', '-3.333333333333E-01', '-8.333333333333E-02']]]

I do not know if creating this list of list of lists is the solution for being able to loop together with for i in xrange(len(P0)): but I cannot manage to accomplish this.

In practice, the VOLUMES list will be of length around ~ 50 items.

Answer 1

Use zip to build your lines, and split the result into len(rows) / len(volumes)-sized blocks. Then, write each block to its respective file.

headers = list(zip(P0, P2))
rows = [row for row in zip(ATOMIC_NUMBERS, Xs, Ys, Zs)]
interval = int(len(rows) / len(VOLUMES))

for block_i, vol_i in zip(range(0, len(rows), interval), range(len(VOLUMES))):
    # Create the lines for the file
    lines = [' '.join(headers[vol_i]), '3']
    lines += [' '.join(row) for row in rows[block_i : block_i + interval]]
    # Write the file
    with open(VOLUMES[vol_i] + '.dat', 'w') as f:
        # Preceding lines
        f.write('some stuff\nother stuff')
        # Lines of data
        for line in lines:
            f.write(line + '\n')
        # Trailing lines
        f.write('other stuff\nsome other stuff')

File 119.823364.dat will contain:

some stuff
some other stuff
4.97568007 16.76591397
3
20 0.000000000000E+00 0.000000000000E+00 0.000000000000E+00
6 3.333333333333E-01 -3.333333333333E-01 -8.333333333333E-02
8 -4.090760942850E-01 -3.333333333333E-01 -8.333333333333E-02
other stuff
some other stuff

Note that this approach is dynamic and will work for a VOLUMES of any length.

Answer 2

The following will create 119.823364.dat:

VOLUMES = ['119.823364', '121.143469']
P0 = ['4.97568007', '4.98494429']
P2 = ['16.76591397', '16.88768068']
Xs = ['0.000000000000E+00', '3.333333333333E-01', '-4.090760942850E-01', 
      '0.000000000000E+00', '3.333333333333E-01', '-4.093755657782E-01']
Ys = ['0.000000000000E+00', '-3.333333333333E-01', '-3.333333333333E-01', 
      '0.000000000000E+00', '-3.333333333333E-01', '-3.333333333333E-01']
Zs = ['0.000000000000E+00', '-8.333333333333E-02', '-8.333333333333E-02', 
      '0.000000000000E+00', '-8.333333333333E-02', '-8.333333333333E-02']
ATOMIC_NUMBERS = ['20', '6', '8', '20', '6', '8']

with open('{}.dat'.format(VOLUMES[0]), 'w+') as file:
    file.write('some stuff \n')
    file.write('other stuff \n')
    for item in P0:
        file.write('{}   '.format(item))
    file.write('\n')
    file.write('3 \n')
    for i in range(3):
        file.write('{} {} {} {} \n'.format(ATOMIC_NUMBERS[i], 
                                           Xs[i], Ys[i], Zs[i]))
    file.write('other stuff')

You'd follow a similar process for creating 121.143469.dat