Partial application is a way to create a function by passing only some arguments to a method. The
_ character stands in for missing arguments and becomes an argument to the created function. It only applies to a single method, list, or dictionary call, not to a more complex nested expression.
f is now a function of one argument.
it is equivalent to having written:
(except that there is no name 'x' declared)
g is a function of two arguments.
Here are some example usages of this in a collect message. Below each is written the equivalent function.
An example of what you can't do: