I have a set of lists that look like this:

conditions = [
["condition1", ["sample1", "sample2", "sample3"]],
["condition2", ["sample4", "sample5", "sample6"],
...]

how can I do the following things efficiently and elegantly in Python?

1. Find all the elements in a certain condition?

e.g. get all the samples in condition2. Right now I can do:

for cond in conditions:
  cond_name, samples = cond
  if cond_name == requested_cond:
    return samples

but that's clunky.

1. Find the ordered union of a list of conditions? E.g. ordered_union(["condition1", "condition2"], conditions) should return:

   ["sample1", "sample2", "sample3", "sample4", "sample5", "sample6"]

How can I do this efficiently in Python? There are probably clever one liners?