How to cascade try imports in a readable way

Question

I want to try to import a list of JSON parsing libraries in python, with precedence for item in the order of which they're tried. If I have the following json libraries ajson, bjson, ... I'd have to write something like

try:
    import ajson as json
except ImportError:
    try:
        import bjson as json
    except ImportError:
        try:
            import cjson as json
        except ImportError:
            ...

which is very unreadable. Is there a better way to do this like an if statement?

Answer 1

You could define a function that encapsulates this fallback behavior:

import importlib

def import_fallback(*modules):
  for m in modules:
    try:
      return importlib.import_module(m)
    except ImportError:
      continue
  raise ImportError("All fallback imports failed: {}".format(modules))

# You can use it like this
json = import_fallback("ajson", "bjson", "cjson")

Edit: There might be a downside from doing this. Some linters or static code analyzers might not know that you are importing these modules by running this function