when to use result and return in def function?

Hello Gia, Function is block of code that do certain task in your program. Let's see a simple example

def cal_age(birth_year){ my_age = 2019 - birth_year print(my_age) } In above function we are calcaluting my age. we passed an argument birth_year(ex:1996 my birth_year) now in my_age varivable your calcaluting my age by subtracting it from current year.Now if you want to print the result of the function just print it inside fuction body.When you call the function you will see the my_age gets printed to the console. cal_age(1996) it will print 23 to the console.

now if you want return the value form a function we need to use the return keyword.

def cal_age(birth_year){ my_age = 2019 - birth_year return my_age }

now this function will return the calcaluted value of my_age. It will not print anything on the console when you call the function. To print the value of my_age you need to enclose the function with print statement like this print(cal_age(1996)) or you can use a varivable to store the function return value like this

age = cal_age(1996) print(age) // 23 prints to console