dumping a dictionary to a YAML file while preserving order

Question

I've been trying to dump a dictionary to a YAML file. The problem is that the program that imports the YAML file needs the keywords in a specific order. This order is not alphabetically.

import yaml import os   baseFile = 'myfile.dat' lyml = [{'BaseFile': baseFile}] lyml.append({'Environment':{'WaterDepth':0.,'WaveDirection':0.,'WaveGamma':0.,'WaveAlpha':0.}})  CaseName = 'OrderedDict.yml' CaseDir = r'C:\Users\BTO\Documents\Projects\Mooring code testen' CaseFile = os.path.join(CaseDir, CaseName) with open(CaseFile, 'w') as f:     yaml.dump(lyml, f, default_flow_style=False) 

This produces a *.yml file which is formatted like this:

- BaseFile: myfile.dat - Environment:     WaterDepth: 0.0     WaveAlpha: 0.0     WaveDirection: 0.0     WaveGamma: 0.0 

But what I want is that the order is preserved:

- BaseFile: myfile.dat - Environment:     WaterDepth: 0.0     WaveDirection: 0.0     WaveGamma: 0.0     WaveAlpha: 0.0 

Is this possible?

Answer 1

yaml.dump has a sort_keys keyword argument that is set to True by default. Set it to False to not reorder:

with open(CaseFile, 'w') as f:     yaml.dump(lyml, f, default_flow_style=False, sort_keys=False)