Python nested loop generate coordinate and save them to csv file-CodePudding

I hope somebody can shade some light here and help me to figure out what I am doing wrong.

I am working with Ursina engine to generate some some cube to a given location, as follow

terrain_z_x = 10
terrain_depth = 3

for z in range(terrain_z_x):
    for y in range(terrain_depth):
        for x in range(terrain_z_x):
            if y > 0:
                voxel = Voxel(position=(x,-y,z))
            else:
                voxel = Voxel(position=(x,-y,z))
            terrain_dictionary["Object"] = "Cube"
            terrain_dictionary["x"] = voxel.position.x
            terrain_dictionary["y"] = voxel.position.y
            terrain_dictionary["z"] = voxel.position.z

This generate 10 cubes on the z and x axis and 3 on the y. This works perfectly and I don't have any issue. But what I wanted to do, is while I am looping over those coordinates to save them into a csv file to have a list of all the cubes that are present in the engine.

so I imported csv library and updated my code as follow.

for z in range(terrain_z_x):
    for y in range(terrain_depth):
        for x in range(terrain_z_x):
            if y > 0:
                voxel = Voxel(position=(x,-y,z))
            else:
                voxel = Voxel(position=(x,-y,z))
            terrain_dictionary["Object"] = "Terrain"
            terrain_dictionary["x"] = voxel.position.x
            terrain_dictionary["y"] = voxel.position.y
            terrain_dictionary["z"] = voxel.position.z

with open("position.csv", 'w') as position:
    writer = csv.DictWriter(position, terrain_info)
    writer.writeheader()
    writer.writerow(terrain_dictionary)

This works but not as expected. Because on the csv file, I have only the last looped position.

Object,x,y,z
Cube,9.0,-2.0,9.0

I am having some hard time to understand how I can save each given position to the csv file while performing the loop and have a csv file like this:

Object,x,y,z
Cube,0,0,0
Cube,0,0,1
......
Cube, 9,-2,9

If hope I made my question and issue clear, if not please do not hesitate to ask more details.

Thank you so much in advance

CodePudding user response：

At the end of the triple for loop, the dictionary terrain_dictionary only has 4 keys with the last values in them. You should append each dictionary in a list of dict, then loop on this list to write each dictionary in the CSV file.

dict_list = []
for z in range(terrain_z_x):
    for y in range(terrain_depth):
        for x in range(terrain_z_x):
            if y > 0:
                voxel = Voxel(position=(x,y,z)) # I guess the - sign was a mistake ?
            else:
                voxel = Voxel(position=(x,-y,z))
            terrain_dictionary["Object"] = "Terrain"
            terrain_dictionary["x"] = voxel.position.x
            terrain_dictionary["y"] = voxel.position.y
            terrain_dictionary["z"] = voxel.position.z
            # Insert a copy of the dictionary in the list
            dict_list.append(terrain_dictionary.copy())

with open("position.csv", 'w') as position:
    writer = csv.DictWriter(position, terrain_info)
    writer.writeheader()
    for d in dict_list:
        writer.writerow(d)