Most Pythonic method of conditionally extracting data from multiple lists of dictionaries

Question

I'm trying to use two lists of dictionaries to build an object, the dictionaries are built from a TAP connection to two different databases. Because of the data sources I cannot guarantee that any of the dictionaries will contain the information I need, so I've chosen a primary dictionary and if the information is not in there then I extract it from the second dictionary.

Because I'm pulling the data from two different data sources, the field names from TAP differ for both sources, so I can't just do an intersection of the dictionaries.

At the moment I can get it to work, but I'm not happy with the solution:

for result in eeuresults:
    name=result['target_name']
    axes=result['semi_major_axis']
    period=result['period']
    radius=result['radius']

    if math.isnan(period):
        for r in eparesults:
            if r['pl_name'] == name: period=r['pl_orbper']
    if math.isnan(axes):
        for r in eparesults:
            if r['pl_name'] == name: axes=r['pl_orbsmax']        
    if math.isnan(radius):
        for r in eparesults:
            if r['pl_name'] == name: radius=r['pl_radj']

I've tried using dictionary.get() to make it simpler, but it falls down if the value isn't in the second list of dictionaries.

axes=result.get('semi_major_axis',[r['pl_orbper'] for r in eparesults if r['pl_name']==name][0])

Edit: Solution Chosen

I ended up using rioV8's solution to reduce code duplication, it's not the most efficient solution, but it is elegant, readable and expandable; which is what I really wanted. Full function is below:

def getsystemdata(name, epaname=None):
    def search_epa(name, value, key):
        if math.isnan(value):
            for r in eparesults:
                if r['pl_name'] == name: return r[key]
        return value
            
    if epaname == None: epaname=name
    service=pyvo.dal.TAPService("https://exoplanetarchive.ipac.caltech.edu/TAP")
    eparesults=service.search(f"select pl_name, pl_radj, pl_orbper, pl_orbsmax from pscomppars where hostname = '{epaname}' ")
    
    service=pyvo.dal.TAPService("http://voparis-tap-planeto.obspm.fr/tap")
    eeuresults=service.search(f"select target_name, radius, period, semi_major_axis from exoplanet.epn_core where star_name = '{name}'")
    
    planets=[]
    for result in eeuresults:
        name=result['target_name']
        axes=search_epa(name, result['semi_major_axis'], 'pl_orbsmax')
        period=search_epa(name, result['period'], 'pl_orbper')
        radius=search_epa(name, result['radius'], 'pl_radj')

        planets.append(Planet(name.split(' ')[-1], axes, period, radius))

    return planets

Answer 1

remove code duplication

def find_in_eparesults(name, value, epa_key):
  if math.isnan(value):
    for r in eparesults:
      if r['pl_name'] == name:
        value = r[epa_key]
        break
  return value

for result in eeuresults:
    name=result['target_name']
    axes=find_in_eparesults(name, result['semi_major_axis'], 'pl_orbper')
    period=find_in_eparesults(name, result['period'], 'pl_orbsmax')
    radius=find_in_eparesults(name, result['radius'], 'pl_radj')