4a_higherorderfunctions.md

Higher Order Functions

Python functions are first-class, meaning they can be manipulated just like any other variable.
The lambda keyword is used to declare an anonymous function (a function without a name).

def flip(f):
    return lambda x, y: f(y, x)

The flip function above takes a function as its parameter and returns an arguments-reversed version

# This code prints "string concatenation" using the above definition of `flip`
print(flip(lambda x, y: x + y)("concatenation", "string"))

Higher-order functions take in a function and do something with it. If a higher-order function takes in a function as its only parameter and returns a function, Python allows the decorator syntax to be used:

@flip
def weird_sub(x, y):
    return x - y

is equivalent to

def weird_sub(x, y):
    return x - y
    
weird_sub = flip(weird_sub)

Next

variadics
more syntax in functions
control structures