In many cases, the definition of a helper function seems to requires too much code. Often, we can digest the key function to a single expression. It can seem wasteful to have to write both def and return statements to wrap a single expression.
Python offers the lambda form as a way to simplify using higher-order functions. A lambda form allows us to define a small, anonymous function. The function's body is limited to a single expression.
The following is an example of using a simple lambda expression as the key:
long = max(trip, key=lambda leg: leg[2])short = min(trip, key=lambda leg: leg[2])
The lambda we've used will be given an item from the sequence; in this case, each leg three tuple will be given to the ...
