Answer:
def list_total(numbers):
sum_of_numbers = 0
for number in numbers:
sum_of_numbers += number
return sum_of_numbers
Step-by-step explanation:
So, to define a function, the syntax is simply:
def functionName(arguments here):
# code
So to define a function called "list_total" which accepts a list of integers, you write:
"
def list_total(numbers):
# code
"
any the "numbers" is a parameter, and it's just like any variable, so you can name it anything besides keywords. I just named it "numbers" since it makes sense in this context, you could also write "integers" instead and it would be just as valid, and may be a bit more specific in this case.
Anyways from here, the initial sum should be equal to 0, and from there we add each number in the list to that initial sum. This can be done by initializing a variable to the value "0" and then traversing the list using a for loop. This can be done as such:
"
def list_total(numbers):
sum_of_numbers = 0
for number in numbers:
# code
"
So for each element or integer in the list "numbers" the for lop will run, and the variable "number" will contain the value of the current element it's on.
So we can add the "number" to the sum_of_numbers as such:
sum_of_numbers = sum_of_numbers + number
but there is a shorter way to do this, and it's represented as:
sum_of_numbers += sum_of_numbers
which will do the same exact thing. In fact this works for any mathematical operation for example:
a *= 3
is the same thing as
a = a * 3
and
a /= 3
is the same thing as
a = a / 3
It's the same thing, but it's a much shorter and more readable notation.
Anyways, this code will go in the for loop to almost finish the code
"
def list_total(numbers):
sum_of_numbers = 0
for number in numbers:
sum_of_numbers += number
"
The last thing is to return this value, and this is simply done by using the syntax:
"return {value here}"
and since the sum_of_numbers has the value, we write
"return sum_of_numbers"
at the end of the function, which is very very important, because when you use the return keyword, you end the function, and return whatever value is next to the return to the function call
So to finish the code we just add this last piece to get:
"
def list_total(numbers):
sum_of_numbers = 0
for number in numbers:
sum_of_numbers += number
return sum_of_numbers
"