Question

Is there a way to map a list onto a dictionary? What I want to do is give it a function that will return the name of a key, and the value will be the original value. For example;

somefunction(lambda a: a[0], ["hello", "world"])
=> {"h":"hello", "w":"world"}

(This isn’t a specific example that I want to do, I want a generic function like map() that can do this)

Answer 1

I don’t think a standard function exists that does exactly that, but it’s very easy to construct one using the dict builtin and a comprehension:

def somefunction(keyFunction, values):
    return dict((keyFunction(v), v) for v in values)

print somefunction(lambda a: a[0], ["hello", "world"])

Output:

{'h': 'hello', 'w': 'world'}

But coming up with a good name for this function is more difficult than implementing it. I’ll leave that as an exercise for the reader.